2,294 research outputs found
Floristic Investigation of Crooked Creek Community of Juan Solomon Park, Indianapolis Indiana
The protection of plant resources in urban areas is a growing conservation concern. Inventory activities that document species presence and stewardship plans that protect and enhance these areas are needed. The results of a botanical inventory of the Crooked Creek Community Juan Solomon Park in Indianapolis, Indiana, are reported in this paper. The 46-acre park contains three distinct habitats, supporting a wide variety of plants. One hundred seventy-nine vascular plant species from 64 families were identified, including 53 (29.6%) non-native species that are naturalizing within the park. Despite its high percentage of alien species and urban setting, the park is an important natural area. The flora\u27s coefficient of conservatism (sense Swink and Wilhelm, 1994) was 54.1. Several exotic, invasive species (most notably garlic mustard, amur bush honeysuckle, and wintercreeper) pose potential future threats to the park\u27s natural flora, and management efforts should be focused on their removal
A Predictive Model for Human-Unmanned Vehicle Systems : Final Report
Advances in automation are making it possible for a single operator to control multiple unmanned
vehicles (UVs). This capability is desirable in order to reduce the operational costs of human-UV systems
(HUVS), extend human capabilities, and improve system effectiveness. However, the high complexity
of these systems introduces many significant challenges to system designers. To help understand and
overcome these challenges, high-fidelity computational models of the HUVS must be developed. These
models should have two capabilities. First, they must be able to describe the behavior of the various
entities in the team, including both the human operator and the UVs in the team. Second, these models
must have the ability to predict how changes in the HUVS and its mission will alter the performance
characteristics of the system. In this report, we describe our work toward developing such a model. Via
user studies, we show that our model has the ability to describe the behavior of a HUVS consisting of a
single human operator and multiple independent UVs with homogeneous capabilities. We also evaluate
the model’s ability to predict how changes in the team size, the human-UV interface, the UV’s autonomy
levels, and operator strategies affect the system’s performance.Prepared for MIT Lincoln Laborator
Identifying Predictive Metrics for Supervisory Control of Multiple Robots
In recent years, much research has focused on making possible single operator control of multiple robots. In these high workload situations, many questions arise including how many robots should be in the team, which autonomy levels should they employ, and when should these autonomy levels
change? To answer these questions, sets of metric classes should be identified that capture these aspects of the human-robot team. Such a set of metric classes should have three properties. First, it should contain the key performance parameters of the system. Second, it should identify the limitations of the agents in the system. Third, it should have predictive power. In this paper, we decompose a human-robot team consisting of a single human and multiple robots in an effort to identify such a set of metric classes.
We assess the ability of this set of metric classes to (a) predict the number of robots that should be in the team and (b) predict system effectiveness. We do so by comparing predictions with actual data from a user study, which is also described.This research was funded by MIT Lincoln Laboratory
A differential method for bounding the ground state energy
For a wide class of Hamiltonians, a novel method to obtain lower and upper
bounds for the lowest energy is presented. Unlike perturbative or variational
techniques, this method does not involve the computation of any integral (a
normalisation factor or a matrix element). It just requires the determination
of the absolute minimum and maximum in the whole configuration space of the
local energy associated with a normalisable trial function (the calculation of
the norm is not needed). After a general introduction, the method is applied to
three non-integrable systems: the asymmetric annular billiard, the many-body
spinless Coulombian problem, the hydrogen atom in a constant and uniform
magnetic field. Being more sensitive than the variational methods to any local
perturbation of the trial function, this method can used to systematically
improve the energy bounds with a local skilled analysis; an algorithm relying
on this method can therefore be constructed and an explicit example for a
one-dimensional problem is given.Comment: Accepted for publication in Journal of Physics
A UAV Mission Hierarchy
In the following sections, each of the primary missions are decomposed into mission planning, management, and replanning segments in order to identify
what the primary functions a human operator will need to perform. The goal is to understand what tasks/functions are common across different UAV
missions and platforms in order to map the generalizability of any particular research project.Prepared for Charles River Analytic
Weaning Weight Summary for South Dakota Livestock Production Records Association Member Herds Using Crossbreeding
The primary objective of this study was to provide members of the Production Records Association an analysis of the weaning weights of various crossbreds produced in member herds. The results should form an important part of the total information needed by members and other cattlemen to formulate individual breeding programs
Fast computation of Bernoulli, Tangent and Secant numbers
We consider the computation of Bernoulli, Tangent (zag), and Secant (zig or
Euler) numbers. In particular, we give asymptotically fast algorithms for
computing the first n such numbers in O(n^2.(log n)^(2+o(1))) bit-operations.
We also give very short in-place algorithms for computing the first n Tangent
or Secant numbers in O(n^2) integer operations. These algorithms are extremely
simple, and fast for moderate values of n. They are faster and use less space
than the algorithms of Atkinson (for Tangent and Secant numbers) and Akiyama
and Tanigawa (for Bernoulli numbers).Comment: 16 pages. To appear in Computational and Analytical Mathematics
(associated with the May 2011 workshop in honour of Jonathan Borwein's 60th
birthday). For further information, see
http://maths.anu.edu.au/~brent/pub/pub242.htm
Dynamical response of the "GGG" rotor to test the Equivalence Principle: theory, simulation and experiment. Part I: the normal modes
Recent theoretical work suggests that violation of the Equivalence Principle
might be revealed in a measurement of the fractional differential acceleration
between two test bodies -of different composition, falling in the
gravitational field of a source mass- if the measurement is made to the level
of or better. This being within the reach of ground based
experiments, gives them a new impetus. However, while slowly rotating torsion
balances in ground laboratories are close to reaching this level, only an
experiment performed in low orbit around the Earth is likely to provide a much
better accuracy.
We report on the progress made with the "Galileo Galilei on the Ground" (GGG)
experiment, which aims to compete with torsion balances using an instrument
design also capable of being converted into a much higher sensitivity space
test.
In the present and following paper (Part I and Part II), we demonstrate that
the dynamical response of the GGG differential accelerometer set into
supercritical rotation -in particular its normal modes (Part I) and rejection
of common mode effects (Part II)- can be predicted by means of a simple but
effective model that embodies all the relevant physics. Analytical solutions
are obtained under special limits, which provide the theoretical understanding.
A simulation environment is set up, obtaining quantitative agreement with the
available experimental data on the frequencies of the normal modes, and on the
whirling behavior. This is a needed and reliable tool for controlling and
separating perturbative effects from the expected signal, as well as for
planning the optimization of the apparatus.Comment: Accepted for publication by "Review of Scientific Instruments" on Jan
16, 2006. 16 2-column pages, 9 figure
Pricing Options in Incomplete Equity Markets via the Instantaneous Sharpe Ratio
We use a continuous version of the standard deviation premium principle for
pricing in incomplete equity markets by assuming that the investor issuing an
unhedgeable derivative security requires compensation for this risk in the form
of a pre-specified instantaneous Sharpe ratio. First, we apply our method to
price options on non-traded assets for which there is a traded asset that is
correlated to the non-traded asset. Our main contribution to this particular
problem is to show that our seller/buyer prices are the upper/lower good deal
bounds of Cochrane and Sa\'{a}-Requejo (2000) and of Bj\"{o}rk and Slinko
(2006) and to determine the analytical properties of these prices. Second, we
apply our method to price options in the presence of stochastic volatility. Our
main contribution to this problem is to show that the instantaneous Sharpe
ratio, an integral ingredient in our methodology, is the negative of the market
price of volatility risk, as defined in Fouque, Papanicolaou, and Sircar
(2000).Comment: Keywords: Pricing derivative securities, incomplete markets, Sharpe
ratio, correlated assets, stochastic volatility, non-linear partial
differential equations, good deal bound
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