• Title/Summary/Keyword: Large Objects

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Gravitational-Wave Astronomy (중력파 천문학)

  • Kim, Chunglee
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.31.3-31.3
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    • 2016
  • Exploring a universe with gravitational waves (GWs) was only theoretical expectation for long time. In September 2015, the Laser Interferometer GW Observatory (LIGO) first detected GWs emitted from the collision of two stellar-mass black holes in cosmological distance (1.3 billion light years) on Earth. This confirms the existence of black-hole binary mergers, and further, opens a new field of GW astronomy. We begin our discussion with a list of important GW sources that can be detectable on Earth by large-scale laser interferometers such as LIGO. Focusing on compact objects such as neutron stars and black holes, we then discuss possible research in the context of GW astronomy. By coordinating with existing observatories, searching for electromagnetic waves or particles from astronomical objects, around the world, multi-messenger astronomy for the universe's most cataclysmic phenomena (e.g. gamma-ray bursts) will be available in the near future.

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Study of Transients at BOAO

  • Im, Myungshin
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.61.1-61.1
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    • 2016
  • As a new way to explore the universe, astronomers are now performing time-domain astronomy by surveying the universe looking for new transient phenomena and taking movies of the universe with telescopes. Large-area, time-series survey of astronomical objects are uncovering many interesting, fast-changing objects that have now been poorly understood before, such as GRBs, tidal disruption phenomena, and new types of supernova. In order to characterize these new, exciting events, it is very critical to perform follow-up observations, and 1-2m telescopes can effectively contribute to such efforts. Since 2007, our group has been performing follow-up observations of gamma-ray bursts (GRBs) and interesting transients using BOAO and other KASI facilities. Here, we present results from several key transient studies that were done by using BOAO: (1) tidal disruption event Swift J1644+57; (2) SN 2011fe that occurred in M101; and (3) several GRB events. These study demonstrates the usefulness of BOAO as a powerful transient follow-up facility. Finally, we will discuss how BOAO research activities can possibly be bolstered in this newly emerging field of astronomy.

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The Types and Management of Differentiating Consumption depends on the social class of Korean consumers

  • LEE, Jaemin
    • Journal of Wellbeing Management and Applied Psychology
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    • v.2 no.1
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    • pp.35-39
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    • 2019
  • This paper presents two social and academic studies on the boundary between cultural production and consumption. The first line of the study on cultural omnivore analyzes the choice of heterogeneous audiences in the face of various cultural offerings. The second line is a study of market categories, which analyzes the responses of peer audiences to objects with different levels of category code compliance. As such, this paper developed a heterogeneous audience model to evaluate objects of different types. This allows us to consider two dimensions of cultural preference: diversity and orientation of selection. To this end, this paper proposes a new analytical frame work to map consumption behavior on these two dimensions. The results suggest that one type of target that values diversity and transformation is particularly resistant to those that span boundaries. We test this argument in the analysis of two large data sets on film and restaurant reviews. Overall, our findings can extend beyond cultural consumption. Outline variability of contextual individuals or individuals in the same situation can cross cultural boundaries even if they are not intentionally pursuing such hybridism.

O Valor Documental dos Balangandãs: Uma Análise Simbólica e Formal

  • Carmo, Sura Souza;Borges, Luiz C.
    • Iberoamérica
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    • v.23 no.1
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    • pp.79-111
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    • 2021
  • The purpose of this article is to present the potential of balangandãs as a documentary source for intersectional studies of gender and slavery, from the analysis of formal and symbolic aspects of the museum objects in the Museu Nacional Nacional (MHN) and Museu Carlos Costa Pinto (MCCP). Balangandãs are a type of creole jewelry, made in gold or silver and used in Brazil since the 18th century by black women - women who worked, especially in the commercialization of foodstuffs in large urban centers. They are described in printed sources and engravings, and preserved in some museum institutions. In the study, the meanings attributed to the object over the centuries are observed: jewelry, amulet, peculium, document, travel memory and heritage. As a result, the article seeks to highlight the objects as a historical and documentary source, verifying similarities between the pieces musealized at the MHN and at the MCCP, also emphasizing the documental power of the pieces produced today.

CONSTRUCTION LOST-TIME INJURIES IN LAOS: AN EXPLORATORY STUDY

  • Luu Truong Van;Soo-Yong Kim;Somsana T.K.P
    • International conference on construction engineering and project management
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    • 2007.03a
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    • pp.229-238
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    • 2007
  • This paper presents a study on construction safety in the People Democratic Republic of Laos (PDRL). Fifty workers experienced certain injuries in their construction sites and 15 top managers were interviewed in twenty-six construction projects in Vientiane, the capital of PDRL. Research results show that stepping on and/or striking against objects (48%), struck by falling objects (24%), falling of persons (12%) are major types of construction injuries. The paper stresses that the ignorance of top managers about their crucial role in safety improvement, using safety incentive to raise safety performance, lack of thorough understanding about benefit from labor safety performance, and the willingness to cut off safety performance expenditures is considered as obstructions of safety improvement programs. The survey indicates that physical working conditions, relationship among workers, foremen behaviors and the monthly wage were influencing factors to worker's job satisfaction. The study also highlights afternoon as dominant time that led to a large number of injuries.

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Taxonomic Classification of Asteroids in Photometry with KMTNet

  • Choi, Sangho;Moon, Hong-Kyu;Roh, Dong-Goo;Chiang, Howoo;Sohn, Young-Jong
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.71.2-71.2
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    • 2019
  • In order to gather clues to surface mineralogy of asteroids, we classify their taxonomy based on their reflected spectra. It is remarkable that a large number of asteroids plotted in the proper orbital element space with distinct colors according to their taxonomic types reveal the dynamical evolution and the structure in the near-Earth space, the main-belt and beyond. Although we have ~1×106 known objects, no more than ~3×103 of them are properly classified taxonomically as visible-near infrared spectroscopy is costly. On the other hand, multi-wavelength broadband photometry in the visible region provides a rather inexpensive alternative tool for approximate taxonomy. Thus we have conducted multi-band observations systematically using Korea Microlensing Telescope Network (KMTNet) with BVRI and griz filters since back in 2015. We then applied aperture photometry with elliptical apertures to fit the trails of objects during the exposures, and classified them with the principle component indices of Ivezic et al. (2001). We will make use of our new, three dimensional asteroid classification scheme for the next step.

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Development of a 3D earthwork model based on reverse engineering

  • Kim, Sung-Keun
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.641-642
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    • 2015
  • Unlike for other building processes, BIM for earthwork does not need a large variety of 3D model shapes; however, it requires a 3D model that can efficiently reflect the changing features of the ground shape and provide soil type-dependent workload calculation and information on equipment for optimal management. Objects for earthwork have not yet been defined because the current BIM system does not provide them. The BIM technology commonly applied in the manufacturing center uses real-object data obtained through 3D scanning to generate 3D parametric solid models. 3D scanning, which is used when there are no existing 3D models, has the advantage of being able to rapidly generate parametric solid models. In this study, A method to generate 3D models for earthwork operations using reverse engineering is suggested. 3D scanning is used to create a point cloud of a construction site and the point cloud data are used to generate a surface model, which was then converted into a parametric model with 3D objects for earthwork

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STag: Supernova Tagging and Classification

  • Davison, William;Parkinson, David;Tucker, Brad E.
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.45.3-46
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    • 2021
  • Supernovae classes have been defined phenomenologically, based on spectral features and time series data, since the specific details of the physics of the different explosions remain unrevealed. However, the number of these classes is increasing as objects with new features are observed, and the next generation of large-surveys will only bring more variety to our attention. We apply the machine learning technique of multi-label classification to the spectra of supernovae. By measuring the probabilities of specific features or 'tags' in the supernova spectra, we can compress the information from a specific object down to that suitable for a human or database scan, without the need to directly assign to a reductive 'class'. We use logistic regression to assign tag probabilities, and then a feed-forward neural network to filter the objects into the standard set of classes, based solely on the tag probabilities. We present STag, a software package that can compute these tag probabilities and make spectral classifications.

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Scattering Model for Electrical-Large Target Employing MLFMA and Radar Imaging Formation

  • Wu, Xia;Jin, Yaqiu
    • Journal of electromagnetic engineering and science
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    • v.10 no.3
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    • pp.166-170
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    • 2010
  • To numerically calculate electromagnetic scattering from the electrical-large three-dimensional(3D) objects, the high-frequency approaches have been usually applied, but the accuracy and feasibility of these geometrical and physical optics(GO-PO) approaches, to some extent, are remained to be improved. In this paper, a new framework is developed for calculation of the near-field scattering field of an electrical-large 3D target by using a multilevel fast multipole algorithm(MLFMA) and generation of radar images by using a fast back-projection(FBP) algorithm. The MPI(Message Passing Interface) parallel computing is carried out to multiply the calculation efficiency greatly. Finally, a simple example of perfectly electrical conducting(PEC) patch and a canonical case of Fighting Falcon F-16 are presented.

Real-Time Simulation of Thin Rod

  • Choi, Min Gyu;Song, Oh-Young
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.4
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    • pp.849-859
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    • 2013
  • This paper proposes a real-time simulation technique for thin rods undergoing large rotational deformation. Rods are thin objects such as ropes and hairs that can be abstracted as one-dimensional structures. Development of a real-time physical model that can produce visually convincing animation of thin rods has been a challenging problem in computer graphics. We adopt continuum mechanics to formulate the governing equation, and develop a modal warping technique for rods to integrate the governing equation in real-time; This is a novel extension of the previous modal warping techniques developed for solids and shells. Experimental results show that the proposed method runs in real-time even for large meshes and it can simulate large bending and/or twisting deformations.