558 research outputs found
Could and Should America Have Made an Ottoman Republic in 1919?
Numerous Americans, perhaps especially American lawyers, have since the 1780s presumed to tell other peoples how to govern themselves. In 2006, that persistent impulse was once again echoed in an address to the American Bar Association by a Justice of the Supreme Court. The purpose of this essay is to question the wisdom of this evangelical ambition, especially when the form of instruction includes military force. It is draws on Spreading America\u27s Word (2005) and directs attention to the hopes of American Protestant Zionists to make a democratic republic in Ottoman Palestine. It suggests that chances were better in 1919 than they are in 2008, but were none to good at that time. It rejects the appeal of the militant neo-conservatives who expressed their hopes and expectations in The Project for A New American Century, an instrument that should be read and remembered for centuries to come
Lateral Resistance of Buried Pipes by Frictional Limit Analysis
Pipelines are vital means of transportation of liquids and gases over large geographical areas. Regarding buried pipes, they are submitted to thermal and mechanical loads due to their support conditions, pipe-soil friction and the surrounding soil mass. Under high compressive loads carried out by these efforts, loss of stability and buckling may occur. Then, the evaluation of soil lateral resistance that will cause a imminent breakout is important. This work aims the analysis of the soil lateral resistance by frictional limit analysis formulation, considering the soil mass as a deformable body and the pipe as a rigid one. An yield function considering material porosity and material friction angle is considered. The soil lateral resistance forces obtained from the proposed formulation are compared to a those ones considering the limit analysis lower bound found in literature. The fully bounded condition observed in most models is also discussed
Usefulness and perceived usefulness of decision support systems (DSSs) in participatory forest planning: the final user's point of view
In recent decades, the focus of forestry Decision Support Systems (DSSs) has expanded
to consider the social dimension of forestry and to support participatory decision-making.
A large number of models and tools have become available to solve forest management
planning problems. The Usefulness of a DSS depends on the range of tools that
it incorporates, and many researches have been developed to evaluate DSSs using Usefulness
as parameter. The assessment of Usefulness concerns the effectiveness of a
DSS. Furthermore, most assessments take into account the degree of Perceived Usefulness,
which is considered an indicator of the impact a system has on job performance.
The present study focuses on the analysis of final users’ point of view on the Usefulness
and Perceived Usefulness of DSSs in participatory forest planning. The research
investigates how forest users’ characteristics and context influence their views on the
potentialities of DSSs to enhance both the various phases of the participatory planning
process (Usefulness) and job performance (Perceived Usefulness). The study is based
on quantitative data collected through two questionnaires e-mailed to a sample of 150
DSSs end users. The questionnaires focused on Usefulness and on Perceived Usefulness
topics, respectively. Results indicate that special attention must be given to motivating
respondents with a clear explanation of the survey objectives when e-mailing questionnaires.
Moreover, results show that, in general, respondents consider DSSs useful at
each step of the participatory process, despite differences emerge among steps. The
research also shows that respondents’ Perceived Usefulness of DSSs was higher before
actually engaging with DSSs. Furthermore, the results highlight differences in Perceived
Usefulness to improve job performance, suggesting that the use of DSSs may actually
improve job performance more than expected. Specifically, results indicate that
improving the technical descriptions of methodologies incorporated in a DSS may contribute
to increasing the Perceived Usefulness. The information provided within this
research contributes to the advancement of knowledge regarding the Usefulness of
DSSs as perceived by forest stakeholders, which in turn supports the improvement of
DSS architectures and the development of participatory processes in forest management
planninginfo:eu-repo/semantics/publishedVersio
Learning to Simulate Tree-Branch Dynamics for Manipulation
We propose to use a simulation driven inverse inference approach to model the
joint dynamics of tree branches under manipulation. Learning branch dynamics
and gaining the ability to manipulate deformable vegetation can help with
occlusion-prone tasks, such as fruit picking in dense foliage, as well as
moving overhanging vines and branches for navigation in dense vegetation. The
underlying deformable tree geometry is encapsulated as coarse spring
abstractions executed on parallel, non-differentiable simulators. The implicit
statistical model defined by the simulator, reference trajectories obtained by
actively probing the ground truth, and the Bayesian formalism, together guide
the spring parameter posterior density estimation. Our non-parametric inference
algorithm, based on Stein Variational Gradient Descent, incorporates
biologically motivated assumptions into the inference process as neural network
driven learnt joint priors; moreover, it leverages the finite difference scheme
for gradient approximations. Real and simulated experiments confirm that our
model can predict deformation trajectories, quantify the estimation
uncertainty, and it can perform better when base-lined against other inference
algorithms, particularly from the Monte Carlo family. The model displays strong
robustness properties in the presence of heteroscedastic sensor noise;
furthermore, it can generalise to unseen grasp locations.Comment: 8 pages, 9 figure
Path Signatures for Diversity in Probabilistic Trajectory Optimisation
Motion planning can be cast as a trajectory optimisation problem where a cost
is minimised as a function of the trajectory being generated. In complex
environments with several obstacles and complicated geometry, this optimisation
problem is usually difficult to solve and prone to local minima. However,
recent advancements in computing hardware allow for parallel trajectory
optimisation where multiple solutions are obtained simultaneously, each
initialised from a different starting point. Unfortunately, without a strategy
preventing two solutions to collapse on each other, naive parallel optimisation
can suffer from mode collapse diminishing the efficiency of the approach and
the likelihood of finding a global solution. In this paper we leverage on
recent advances in the theory of rough paths to devise an algorithm for
parallel trajectory optimisation that promotes diversity over the range of
solutions, therefore avoiding mode collapses and achieving better global
properties. Our approach builds on path signatures and Hilbert space
representations of trajectories, and connects parallel variational inference
for trajectory estimation with diversity promoting kernels. We empirically
demonstrate that this strategy achieves lower average costs than competing
alternatives on a range of problems, from 2D navigation to robotic manipulators
operating in cluttered environments
DEMON: a Proposal for a Satellite-Borne Experiment to study Dark Matter and Dark Energy
We outline a novel satellite mission concept, DEMON, aimed at advancing our
comprehension of both dark matter and dark energy, taking full advantage of two
complementary methods: weak lensing and the statistics of galaxy clusters. We
intend to carry out a 5000 sqdeg combined IR, optical and X-ray survey with
galaxies up to a redshift of z~2 in order to determine the shear correlation
function. We will also find ~100000 galaxy clusters, making it the largest
survey of this type to date. The DEMON spacecraft will comprise one IR/optical
and eight X-ray telescopes, coupled to multiple cameras operating at different
frequency bands. To a great extent, the technology employed has already been
partially tested on ongoing missions, therefore ensuring improved reliability.Comment: 12 pages, 3 figures, accepted for publication in the SPIE conference
proceeding
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