7,806 research outputs found
Structural Return Maximization for Reinforcement Learning
Batch Reinforcement Learning (RL) algorithms attempt to choose a policy from
a designer-provided class of policies given a fixed set of training data.
Choosing the policy which maximizes an estimate of return often leads to
over-fitting when only limited data is available, due to the size of the policy
class in relation to the amount of data available. In this work, we focus on
learning policy classes that are appropriately sized to the amount of data
available. We accomplish this by using the principle of Structural Risk
Minimization, from Statistical Learning Theory, which uses Rademacher
complexity to identify a policy class that maximizes a bound on the return of
the best policy in the chosen policy class, given the available data. Unlike
similar batch RL approaches, our bound on return requires only extremely weak
assumptions on the true system
SOAP Services with Clarens: Guide for Developers and Administrators
The Clarens application server enables secure, asynchronous SOAP services to run on a Grid cluster such as one of those of the TeraGrid. There is a Client, who wants to use the service and understands the application domain enough to form a reasonable service request; a Developer, who is a power-user of the TeraGrid, who understands both Clarens and the application domain, and creates and deploys a service on a TeraGrid head node; and there is a Root system administrator, who controls the Clarens installation and the cluster on which it runs. The purpose of this document is to provide all of the information a service developer needs to know in order to deploy a Clarens service, with information also provided for the system administrator of the Clarens installation. First we discuss how each of the three roles see the service
The Manifestation of Stress and Rumination in Musicians
Here we offer a brief review of research on individual differences that are common to musicians, focusing on our own work on rumination and stress. Rumination and stress have been linked with depression and negative health outcomes. We discuss two of our published studies and two new, unpublished replications that find elevated levels of rumination and stress in musicians. Further, we review literature that finds this combination of rumination and stress might be especially toxic. Even though people frequently use music to help combat stress, musicians may not be taking advantage of their frequent exposure to music, further exacerbating the problem. Interventions aimed at alleviating stress and rumination might prove helpful to musicians
Alien Registration- Roy, Joseph (Sanford, York County)
https://digitalmaine.com/alien_docs/6171/thumbnail.jp
The Effect of a Reduced-Calorie Diet on alpha-2 Adrenergic Receptor Responsiveness in Abdominal Adipose Tissue in Obese Men During Exercise
There is at present an imperfect understanding of the effect of diet on availability of inhibitory receptors in fat cells during exercise among obese men. 

*Objective:* The purpose of this study was to determine whether diet results in downregulation of alpha-2 adrenergic receptor ([alpha]~2-AR~) messenger RNA (mRNA), improving metabolism in exercise in obese men. 

*Design:* One group, pre-test, post-test design.

*Measurements:* Subcutaneous abdominal adipose tissue was tested for physiologic response, such as changes in catecholamines and other markers of lipolysis measured during periods of exercise, before and after a 12-week diet. Plasma markers of lipolysis/antilipolytic activity (catecholamines [adrenaline and noradrenaline], NEFA, lactate, glucose, hematocrit, or insulin levels) were analyzed at four points in time in order to determine the effect of exercise on [alpha]~2-AR~ and [beta]-AR responsiveness to sympathetic stimulation.

*Subjects:* Otherwise healthy 18 to 45 year old obese men (defined as a body mass index (BMI) over 33 kg/m^2^).

*Results:* The 12-week reduced calorie diet did not result in improved metabolism. Instead, upregulation of alpha-2 adrenergic receptor ([alpha]~2-AR~) messenger RNA (mRNA) was observed. On average, [alpha]~2-AR~ mRNA levels (ratio of [alpha]~2-AR~ to cyclophilin) in subjects increased by 0.022-0.023 after the diet. The average differences in of [alpha]~2-AR~ mRNA and [beta]-AR mRNA measured before and after diet were both insignificant (M = 0.015) t(4) = -0.911; _P_ > 0.05; (M = 0.0139; t(4) = 0.077; _P_ > 0.05). 

*Conclusion:* The observed direction of change in [alpha]~2-AR~ mRNA levels, when viewed together with the stability of [beta]-AR mRNA levels, suggests that upregulation of [alpha]~2-AR~ rather than downregulation occurred. Downregulation would account for decreased lipolytic activity during exercise, future study is needed
Experimental observation of chimera and cluster states in a minimal globally coupled network
A "chimera state" is a dynamical pattern that occurs in a network of coupled
identical oscillators when the symmetry of the oscillator population is broken
into synchronous and asynchronous parts. We report the experimental observation
of chimera and cluster states in a network of four globally coupled chaotic
opto-electronic oscillators. This is the minimal network that can support
chimera states, and our study provides new insight into the fundamental
mechanisms underlying their formation. We use a unified approach to determine
the stability of all the observed partially synchronous patterns, highlighting
the close relationship between chimera and cluster states as belonging to the
broader phenomenon of partial synchronization. Our approach is general in terms
of network size and connectivity. We also find that chimera states often appear
in regions of multistability between global, cluster, and desynchronized
states
Delayed Dynamical Systems: Networks, Chimeras and Reservoir Computing
We present a systematic approach to reveal the correspondence between time
delay dynamics and networks of coupled oscillators. After early demonstrations
of the usefulness of spatio-temporal representations of time-delay system
dynamics, extensive research on optoelectronic feedback loops has revealed
their immense potential for realizing complex system dynamics such as chimeras
in rings of coupled oscillators and applications to reservoir computing.
Delayed dynamical systems have been enriched in recent years through the
application of digital signal processing techniques. Very recently, we have
showed that one can significantly extend the capabilities and implement
networks with arbitrary topologies through the use of field programmable gate
arrays (FPGAs). This architecture allows the design of appropriate filters and
multiple time delays which greatly extend the possibilities for exploring
synchronization patterns in arbitrary topological networks. This has enabled us
to explore complex dynamics on networks with nodes that can be perfectly
identical, introduce parameter heterogeneities and multiple time delays, as
well as change network topologies to control the formation and evolution of
patterns of synchrony
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