SGPN: Similarity Group Proposal Network for 3D Point Cloud Instance Segmentation

We introduce Similarity Group Proposal Network (SGPN), a simple and intuitive deep learning framework for 3D object instance segmentation on point clouds. SGPN uses a single network to predict point grouping proposals and a corresponding semantic class for each proposal, from which we can directly extract instance segmentation results. Important to the effectiveness of SGPN is its novel representation of 3D instance segmentation results in the form of a similarity matrix that indicates the similarity between each pair of points in embedded feature space, thus producing an accurate grouping proposal for each point. To the best of our knowledge, SGPN is the first framework to learn 3D instance-aware semantic segmentation on point clouds. Experimental results on various 3D scenes show the effectiveness of our method on 3D instance segmentation, and we also evaluate the capability of SGPN to improve 3D object detection and semantic segmentation results. We also demonstrate its flexibility by seamlessly incorporating 2D CNN features into the framework to boost performance

Extinction map of the Small Magellanic Cloud based on SIRIUS and 6X 2MASS point source catalogs

In this paper, we present the first extinction map of the Small Magellanic Cloud (SMC) constructed using the color excess at near-infrared wavelengths. Using a new technique named "X percentile method", which we developed recently to measure the color excess of dark clouds embedded within a star distribution, we have derived an E(J – H) map based on the SIRIUS and 6X Two Micron All Sky Survey (2MASS) star catalogs. Several dark clouds are detected in the map derived from the SIRIUS star catalog, which is deeper than the 6X 2MASS catalog. We have compared the E(J – H) map with a model calculation in order to infer the locations of the clouds along the line of sight, and found that many of them are likely to be located in or elongated toward the far side of the SMC. Most of the dark clouds found in the E(J – H) map have counterparts in the CO clouds detected by Mizuno et al. with the NANTEN telescope. A comparison of the E(J – H) map with the virial mass derived from the CO data indicates that the dust-to-gas ratio in the SMC varies in the range A_V /N_H = 1-2 × 10^(–22) mag H^-1 cm^2 with a mean value of ~1.5 × 10^(–22) mag H^-1 cm^2. If the virial mass underestimates the true cloud mass by a factor of ~2, as recently suggested by Bot et al., the mean value would decrease to ~8×10^(–23) mag H^-1 cm^2, in good agreement with the value reported by Gordon et al., 7.59 × 10^(–23) mag H^-1 cm^2

Phase Functions and Light Curves of Wide Separation Extrasolar Giant Planets

We calculate self-consistent extrasolar giant planet (EGP) phase functions and light curves for orbital distances ranging from 0.2 AU to 15 AU. We explore the dependence on wavelength, cloud condensation, and Keplerian orbital elements. We find that the light curves of EGPs depend strongly on wavelength, the presence of clouds, and cloud particle sizes. Furthermore, the optical and infrared colors of most EGPs are phase-dependent, tending to be reddest at crescent phases in $V-R$ and $R-I$. Assuming circular orbits, we find that at optical wavelengths most EGPs are 3 to 4 times brighter near full phase than near greatest elongation for highly-inclined (i.e., close to edge-on) orbits. Furthermore, we show that the planet/star flux ratios depend strongly on the Keplerian elements of the orbit, particularly inclination and eccentricity. Given a sufficiently eccentric orbit, an EGP's atmosphere may make periodic transitions from cloudy to cloud-free, an effect that may be reflected in the shape and magnitude of the planet's light curve. Such elliptical orbits also introduce an offset between the time of the planet's light curve maximum and the time of full planetary phase, and for some sets of orbital parameters, this light curve maximum can be a steeply increasing function of eccentricity. We investigate the detectability of EGPs by proposed space-based direct-imaging instruments.Comment: submitted to Astrophysical Journa

The Mass Distributions of Starless and Protostellar Cores in Gould Belt Clouds

Using data from the SCUBA Legacy Catalogue (850 um) and Spitzer Space Telescope (3.6 - 70 um), we explore dense cores in the Ophiuchus, Taurus, Perseus, Serpens, and Orion molecular clouds. We develop a new method to discriminate submillimeter cores found by SCUBA as starless or protostellar, using point source photometry from Spitzer wide field surveys. First, we identify infrared sources with red colors associated with embedded young stellar objects (YSOs). Second, we compare the positions of these YSO-candidates to our submillimeter cores. With these identifications, we construct new, self-consistent starless and protostellar core mass functions (CMFs) for the five clouds. We find best fit slopes to the high-mass end of the CMFs of -1.26 +/- 0.20, -1.22 +/- 0.06, -0.95 +/- 0.20, and -1.67 +/- 0.72 for Ophiuchus, Taurus, Perseus, and Orion, respectively. Broadly, these slopes are each consistent with the -1.35 power-law slope of the Salpeter IMF at higher masses, but suggest some differences. We examine a variety of trends between these CMF shapes and their parent cloud properties, potentially finding a correlation between the high-mass slope and core temperature. We also find a trend between core mass and effective size, but we are very limited by sensitivity. We make similar comparisons between core mass and size with visual extinction (for A_V >= 3) and find no obvious trends. We also predict the numbers and mass distributions of cores that future surveys with SCUBA-2 may detect in each of these clouds.Comment: 56 pages, 18 figures, fixed typo in Eq 1, results in paper remain unchange

The application of Han Dynasty cultural elements to modern product design

Chinese Han Culture, as Chinese nation's "core culture", is the cultural symbol of Chinese nation, and played an important role in the history of Chinese cultural development, even in the history of world cultural development. Designing in the Han Dynasty, while inheriting Chinese traditional culture, but also having its unique style, are appreciated and respected by the people nowadays. In a modern society where the design is becoming more diversified, the innovative design based on traditional culture and art has its unique charm and vitality. This paper presented our recent research on the application of Han Dynasty cultural elements to modern product design, reflected the local design connotation of Han Dynasty cultural elements