748 research outputs found
Succession of the image of the city in the movement for urban design by local proprietors in Ginza from pre-war to post-war
This paper revealed the development of the movement for urban design by local proprietors in Ginza, Tokyo from 1930’s to 1960’s. Ginza Street is known as one of the first modern style streets in Japan. This street has developed greatly by modern buildings and advanced urban design methods in modern times and after although it has also suffered serious damage twice by Great Kanto Earthquake (1923) and bombing in 1945. Therefore, buildings and urban space have seen repeated reconstruction and renewal until today. On the other hand, if we pay attention to local proprietors, we can understand that they have developed the movement for urban design of Ginza Street continuously and succeeded the awareness of the issues toward urban space. So this paper finds a new historical context of Ginza through the elucidation of development of their movement from viewpoints of how the awareness of the issues and the image of spaces have changed
A Study on Deep CNN Structures for Defect Detection From Laser Ultrasonic Visualization Testing Images
The importance of ultrasonic nondestructive testing has been increasing in
recent years, and there are high expectations for the potential of laser
ultrasonic visualization testing, which combines laser ultrasonic testing with
scattered wave visualization technology. Even if scattered waves are
visualized, inspectors still need to carefully inspect the images. To automate
this, this paper proposes a deep neural network for automatic defect detection
and localization in LUVT images. To explore the structure of a neural network
suitable to this task, we compared the LUVT image analysis problem with the
generic object detection problem. Numerical experiments using real-world data
from a SUS304 flat plate showed that the proposed method is more effective than
the general object detection model in terms of prediction performance. We also
show that the computational time required for prediction is faster than that of
the general object detection model
Simulation-Aided Deep Learning for Laser Ultrasonic Visualization Testing
In recent years, laser ultrasonic visualization testing (LUVT) has attracted
much attention because of its ability to efficiently perform non-contact
ultrasonic non-destructive testing.Despite many success reports of deep
learning based image analysis for widespread areas, attempts to apply deep
learning to defect detection in LUVT images face the difficulty of preparing a
large dataset of LUVT images that is too expensive to scale. To compensate for
the scarcity of such training data, we propose a data augmentation method that
generates artificial LUVT images by simulation and applies a style transfer to
simulated LUVT images.The experimental results showed that the effectiveness of
data augmentation based on the style-transformed simulated images improved the
prediction performance of defects, rather than directly using the raw simulated
images for data augmentation
Near-infrared circular polarization survey in star-forming regions : Correlations and trends
We have conducted a systematic near-infrared circular polarization (CP) survey in star-forming regions, covering high-mass, intermediate-mass, and low-mass young stellar objects. All the observations were made using the SIRPOL imaging polarimeter on the Infrared Survey Facility 1.4 m telescope at the South African Astronomical Observatory. We present the polarization properties of 10 sub-regions in 6 star-forming regions. The polarization patterns, extents, and maximum degrees of linear and circular polarizations are used to determine the prevalence and origin of CP in the star-forming regions. Our results show that the CP pattern is quadrupolar in general, the CP regions are extensive, up to 0.65 pc, the CP degrees are high, up to 20%, and the CP degrees decrease systematically from high- to low-mass young stellar objects. The results are consistent with dichroic extinction mechanisms generating the high degrees of CP in star-forming regions.Peer reviewe
Distortion of Magnetic Fields in a Starless Core II: 3D Magnetic Field Structure of FeSt 1-457
Three dimensional (3D) magnetic field information on molecular clouds and
cores is important for revealing their kinematical stability (magnetic support)
against gravity which is fundamental for studying the initial conditions of
star formation. In the present study, the 3D magnetic field structure of the
dense starless core FeSt 1-457 is determined based on the near-infrared
polarimetric observations of the dichroic polarization of background stars and
simple 3D modeling. With an obtained angle of line-of-sight magnetic
inclination axis of and previously
determined plane-of-sky magnetic field strength of
, the total magnetic field strength for FeSt 1-457 is derived to be
. The critical mass of FeSt 1-457, evaluated using
both magnetic and thermal/turbulent support is
, which is identical to the observed core mass, . We thus conclude that the stability of
FeSt 1-457 is in a condition close to the critical state. Without infalling gas
motion and no associated young stars, the core is regarded to be in the
earliest stage of star formation, i.e., the stage just before the onset of
dynamical collapse following the attainment of a supercritical condition. These
properties would make FeSt 1-457 one of the best starless cores for future
studies of the initial conditions of star formation.Comment: Accepted to the Astrophysical Journal (ApJ
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