7,405 research outputs found
SciTech News Volume 71, No. 1 (2017)
Columns and Reports From the Editor 3
Division News Science-Technology Division 5 Chemistry Division 8 Engineering Division Aerospace Section of the Engineering Division 9 Architecture, Building Engineering, Construction and Design Section of the Engineering Division 11
Reviews Sci-Tech Book News Reviews 12
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SciTech News Volume 70, No. 4 (2016)
Columns and Reports
From the Editor 3
Division News
Science-Technology Division 4
SLA Annual Meeting 2016 Report (S. Kirk Cabeen Travel Stipend Award recipient) 6
Reflections on SLA Annual Meeting (Diane K. Foster International Student Travel Award recipient) 8
SLA Annual Meeting Report (Bonnie Hilditch International Librarian Award recipient)10
Chemistry Division 12
Engineering Division 15
Reflections from the 2016 SLA Conference (SPIE Digital Library Student Travel Stipend recipient)15
Fundamentals of Knowledge Management and Knowledge Services (IEEE Continuing Education Stipend recipient) 17
Makerspaces in Libraries: The Big Table, the Art Studio or Something Else? (by Jeremy Cusker) 19
Aerospace Section of the Engineering Division 21
Reviews
Sci-Tech Book News Reviews 22
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IEEE 17
WeBuyBooks.net 2
Design of strapdown gyroscopes for a dynamic environment Interim scientific report
Error analysis for single degree of freedom integrating gyro, and figure of merit relating gyro errors to orientation error of strapdown inertial reference syste
Proton Irradiation Experiment for the X-ray Charge-Coupled Devices of the Monitor of All-sky X-ray Image mission onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency
We have investigated the radiation damage effects on a CCD to be employed in
the Japanese X-ray astronomy mission including the Monitor of All-sky X-ray
Image (MAXI) onboard the International Space Station (ISS). Since low energy
protons release their energy mainly at the charge transfer channel, resulting a
decrease of the charge transfer efficiency, we thus focused on the low energy
protons in our experiments. A 171 keV to 3.91 MeV proton beam was irradiated to
a given device. We measured the degradation of the charge transfer inefficiency
(CTI) as a function of incremental fluence. A 292 keV proton beam degraded the
CTI most seriously. Taking into account the proton energy dependence of the
CTI, we confirmed that the transfer channel has the lowest radiation tolerance.
We have also developed the different device architectures to reduce the
radiation damage in orbit. Among them, the ``notch'' CCD, in which the buried
channel implant concentration is increased, resulting in a deeper potential
well than outside, has three times higher radiation tolerance than that of the
normal CCD. We then estimated the charge transfer inefficiency of the CCD in
the orbit of ISS, considering the proton energy spectrum. The CTI value is
estimated to be 1.1e-5 per each transfer after two years of mission life in the
worse case analysis if the highest radiation-tolerant device is employed. This
value is well within the acceptable limit and we have confirmed the high
radiation-tolerance of CCDs for the MAXI mission.Comment: 17 pages, 2 table, 12 figures. Accepted for publication of Japanese
Journal of Applied Physics. High resolution file is available from
http://wwwxray.ess.sci.osaka-u.ac.jp/~miyata/paper/proton_cti.pd
Neural Networks for Modeling and Control of Particle Accelerators
We describe some of the challenges of particle accelerator control, highlight
recent advances in neural network techniques, discuss some promising avenues
for incorporating neural networks into particle accelerator control systems,
and describe a neural network-based control system that is being developed for
resonance control of an RF electron gun at the Fermilab Accelerator Science and
Technology (FAST) facility, including initial experimental results from a
benchmark controller.Comment: 21 p
Performance-Barrier-Based Event-Triggered Control with Applications to Network Systems
This paper proposes a novel framework for resource-aware control design
termed performance-barrier-based triggering. Given a feedback policy, along
with a Lyapunov function certificate that guarantees its correctness, we
examine the problem of designing its digital implementation through
event-triggered control while ensuring a prescribed performance is met and
triggers occur as sparingly as possible. Our methodology takes into account the
performance residual, i.e., how well the system is doing in regards to the
prescribed performance. Inspired by the notion of control barrier function, the
trigger design allows the certificate to deviate from monotonically decreasing,
with leeway specified as an increasing function of the performance residual,
resulting in greater flexibility in prescribing update times. We study
different types of performance specifications, with particular attention to
quantifying the benefits of the proposed approach in the exponential case. We
build on this to design intrinsically Zeno-free distributed triggers for
network systems. A comparison of event-triggered approaches in a vehicle
platooning problem shows how the proposed design meets the prescribed
performance with a significantly lower number of controller updates.Comment: 15 pages, 2 figures, submitted to IEEE Transactions on Automatic
Contro
Modeling elucidates how refractory period can provide profound nonlinear gain control to graded potential neurons
Refractory period (RP) plays a central role in neural signaling. Because it limits an excitable membrane's recovery time from a previous excitation, it can restrict information transmission. Classically, RP means the recovery time from an action potential (spike), and its impact to encoding has been mostly studied in spiking neurons. However, many sensory neurons do not communicate with spikes but convey information by graded potential changes. In these systems, RP can arise as an intrinsic property of their quantal micro/nanodomain sampling events, as recently revealed for quantum bumps (single photon responses) in microvillar photoreceptors. Whilst RP is directly unobservable and hard to measure, masked by the graded macroscopic response that integrates numerous quantal events, modeling can uncover its role in encoding. Here, we investigate computationally how RP can affect encoding of graded neural responses. Simulations in a simple stochastic process model for a fly photoreceptor elucidate how RP can profoundly contribute to nonlinear gain control to achieve a large dynamic range. [Abstract copyright: © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
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