5,146 research outputs found
A Postcolonial Study of Organizational Culture and Professional Collaborative Practice in a Southeast Asian International School
International School Philippines (ISP) (a pseudonym) is an international school established during an era of colonization in the Philippines. While the school’s mission has evolved, the organization now navigates a complex postcolonial and cross-cultural landscape. This Organizational Improvement Plan (OIP) problematized the school’s vision of establishing an organizational culture of professional collaborative practice within a culturally diverse teaching faculty. Examining the constructs framing the problem reveals that cross-cultural approaches to human behaviour should consider how individual culture relates to organizational phenomena such as professionalism, collaboration, and leadership. Additionally, leadership approaches chosen to guide organizational change at ISP should be framed in postcolonial and cross-cultural theory. Synthesized through a culturally responsive lens, authentic and adaptive leadership are presented as a singular change leadership approach aligned with ISP’s change context. A critical organizational analysis points to school leadership as the primary driver of organizational change and cultural responsivity as the antecedent to professional collaborative practice in the cross-cultural and postcolonial ISP context. As such, developing culturally responsive leadership throughout the organization is the preferred solution to the problem and the focus of a four-stage change implementation process. Change monitoring—in the form of developmental evaluation (DE) and the plan, do, check, act (PDCA) improvement cycle—and strategic communication are activated throughout the change process. Establishing culturally responsive leadership throughout the organization is believed to be essential to the eventual development of an organizational culture of professional collaborative practice at ISP
Deep Saturated Free Electron Laser Oscillators and Frozen Spikes
We analyze the behavior of Free Electron Laser (FEL) oscillators operating in
the deep saturated regime and point out the formation of sub-peaks of the
optical pulse. They are very stable configurations, having a width
corresponding to a coherence length. We speculate on the physical mechanisms
underlying their growth and attempt an identification with FEL mode locked
structures associated with Super Modes. Their impact on the intra-cavity
nonlinear harmonic generation is also discussed along with the possibility of
exploiting them as cavity out-coupler.Comment: 28 page
Deep Learning for Galaxy Mergers in the Galaxy Main Sequence
Starburst galaxies are often found to be the result of galaxy mergers. As a
result, galaxy mergers are often believed to lie above the galaxy main
sequence: the tight correlation between stellar mass and star formation rate.
Here, we aim to test this claim. Deep learning techniques are applied to images
from the Sloan Digital Sky Survey to provide visual-like classifications for
over 340 000 objects between redshifts of 0.005 and 0.1. The aim of this
classification is to split the galaxy population into merger and non-merger
systems and we are currently achieving an accuracy of 91.5%. Stellar masses and
star formation rates are also estimated using panchromatic data for the entire
galaxy population. With these preliminary data, the mergers are placed onto the
full galaxy main sequence, where we find that merging systems lie across the
entire star formation rate - stellar mass plane.Comment: 4 pages, 1 figure. For Proceedings IAU Symposium No. 34
Identifying Galaxy Mergers in Observations and Simulations with Deep Learning
Mergers are an important aspect of galaxy formation and evolution. We aim to
test whether deep learning techniques can be used to reproduce visual
classification of observations, physical classification of simulations and
highlight any differences between these two classifications. With one of the
main difficulties of merger studies being the lack of a truth sample, we can
use our method to test biases in visually identified merger catalogues. A
convolutional neural network architecture was developed and trained in two
ways: one with observations from SDSS and one with simulated galaxies from
EAGLE, processed to mimic the SDSS observations. The SDSS images were also
classified by the simulation trained network and the EAGLE images classified by
the observation trained network. The observationally trained network achieves
an accuracy of 91.5% while the simulation trained network achieves 65.2% on the
visually classified SDSS and physically classified EAGLE images respectively.
Classifying the SDSS images with the simulation trained network was less
successful, only achieving an accuracy of 64.6%, while classifying the EAGLE
images with the observation network was very poor, achieving an accuracy of
only 53.0% with preferential assignment to the non-merger classification. This
suggests that most of the simulated mergers do not have conspicuous merger
features and visually identified merger catalogues from observations are
incomplete and biased towards certain merger types. The networks trained and
tested with the same data perform the best, with observations performing better
than simulations, a result of the observational sample being biased towards
conspicuous mergers. Classifying SDSS observations with the simulation trained
network has proven to work, providing tantalizing prospects for using
simulation trained networks for galaxy identification in large surveys.Comment: Submitted to A&A, revised after first referee report. 20 pages, 22
figures, 14 tables, 1 appendi
Pathway to a Compact SASE FEL Device
Newly developed high peak power lasers have opened the possibilities of
driving coherent light sources operating with laser plasma accelerated beams
and wave undulators. We speculate on the combination of these two concepts and
show that the merging of the underlying technologies could lead to new and
interesting possibilities to achieve truly compact, coherent radiator devices
Ergodicity breaking in strong and network-forming glassy system
The temperature dependence of the non-ergodicity factor of vitreous GeO,
, as deduced from elastic and quasi-elastic neutron scattering
experiments, is analyzed. The data are collected in a wide range of
temperatures from the glassy phase, up to the glass transition temperature, and
well above into the undercooled liquid state. Notwithstanding the investigated
system is classified as prototype of strong glass, it is found that the
temperature- and the -behavior of follow some of the predictions
of Mode Coupling Theory. The experimental data support the hypothesis of the
existence of an ergodic to non-ergodic transition occurring also in network
forming glassy systems
Above Barrier Dirac Multiple Scattering and Resonances
We extend an above barrier analysis made with the Schrodinger equation to the
Dirac equation. We demonstrate the perfect agreement between the barrier
results and back to back steps. This implies the existence of multiple (indeed
infinite) reflected and transmitted wave packets. These packets may be well
separated in space or partially overlap. In the latter case interference
effects can occur. For the extreme case of total overlap we encounter
resonances. The conditions under which resonance phenomena can be observed is
discussed and illustrated by numerical calculations.Comment: 12 pages, 1 figur
Overcoming the Obfuscation of Java Programs by Identifier Renaming
Decompilation is the process of translating object code to source code and is usually the first step towards the reverse-engineering
of an application. Many obfuscation techniques and tools have been developed, with the aim of modifying a program, such that its
functionalities are preserved, while its understandability is compromised for a human reader or the decompilation is made unsuccessful.
Some approaches rely on malicious identifiers renaming, i.e., on the modification of the program identifiers in order to introduce
confusion and possibly prevent the decompilation of the code.
In this work we introduce a new technique to overcome the obfuscation of Java programs by identifier renaming. Such a technique
relies on the intelligent modification of identifiers in Java bytecode.
We present a new software tool which implements our technique and allows the processing of an obfuscated program in order to
rename the identifiers as required by our technique. Moreover, we show how to use the existing tools to provide a partial implementation
of the technique we propose.
Finally, we discuss the feasibility of our approach by showing how to contrast the obfuscation techniques based on malicious
identifier renaming recently presented in literature
Testing Convolutional Neural Networks for finding strong gravitational lenses in KiDS
Convolutional Neural Networks (ConvNets) are one of the most promising
methods for identifying strong gravitational lens candidates in survey data. We
present two ConvNet lens-finders which we have trained with a dataset composed
of real galaxies from the Kilo Degree Survey (KiDS) and simulated lensed
sources. One ConvNet is trained with single \textit{r}-band galaxy images,
hence basing the classification mostly on the morphology. While the other
ConvNet is trained on \textit{g-r-i} composite images, relying mostly on
colours and morphology. We have tested the ConvNet lens-finders on a sample of
21789 Luminous Red Galaxies (LRGs) selected from KiDS and we have analyzed and
compared the results with our previous ConvNet lens-finder on the same sample.
The new lens-finders achieve a higher accuracy and completeness in identifying
gravitational lens candidates, especially the single-band ConvNet. Our analysis
indicates that this is mainly due to improved simulations of the lensed
sources. In particular, the single-band ConvNet can select a sample of lens
candidates with purity, retrieving 3 out of 4 of the confirmed
gravitational lenses in the LRG sample. With this particular setup and limited
human intervention, it will be possible to retrieve, in future surveys such as
Euclid, a sample of lenses exceeding in size the total number of currently
known gravitational lenses.Comment: 16 pages, 10 figures. Accepted for publication in MNRA
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