• 제목/요약/키워드: barred

검색결과 128건 처리시간 0.023초

이벤트 등록 스패닝트리의 역경로 정보를 이용한 이벤트 라우팅 알고리즘 (Event Routing Algorithms Using the Reverse Paths of Event Subscription Spanning Trees)

  • 류기열;이정태
    • 정보처리학회논문지A
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    • 제9A권1호
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    • pp.19-28
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    • 2002
  • 이벤트에 기반한 약결합의 분산 응용이 인터넷과 같은 광역네트워크 상에서의 주요 응용분야로 대두되고 있다. 이를 지원하기 위해 이벤트 통지서비스가 필요하다. 광역 네트웍크상에서 이벤트 통지 서비스를 구현하는 방법으로 내용기반 이벤트 라우팅이 최근 활발히 연구되고 있다. 본 논문에서는 효과적인 내용기반 이벤트 라우팅 알고리즘을 구현하기 위해 기존에 발표된 대표적인 이벤트 통지서비스 시스템인 SIENA에 바탕을 두고, SIENA에서의 이벤트 라우팅 알고리즘의 문제점을 분석하고 이를 개선한 라우팅 알고리즘을 제안한다.

Secondary bars in barred galaxies

  • Kang, Wongi;Lee, Yun hee;Park, Myeong gu
    • 천문학회보
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    • 제43권2호
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    • pp.54.2-54.2
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    • 2018
  • 나선 은하의 60%의 은하들은 그 중심에 막대를 가지고 있다고 알려져 있다. 그리고 막대 은하들 중 다시 30%의 은하들이 그 중심에 두 번째 막대를 가지고 있다는 보고들이 있었다. 우리는 SDSS/DR7을 기반으로 z < 0.01 안에 은하들을 눈으로 분류한 Ann et al. (2015) 카탈로그 중 Lee et al. (2018, submitted)에서 사용된 Mr = -15.2 보다 밝고, $60^{\circ}$이하로 기울어진 막대 은하 553개를 이용하여 막대 안에 있는 두 번째 막대를 찾고자 했다. 우리는 ellipse fitting profile을 조사하여 58개의 은하들에서 그 중심에 기존 막대의 형태를 따르지 않고 장축이 어긋나 있으며, 타원율에 변화를 보이는 두 번째 막대의 흔적을 찾았다. 그 중 9개의 은하에서 색지도, 등광도 그리고 unsharp image 등에서 두 번째 막대를 확인했다. 이것은 이전의 30개 내외의 은하들를 대상으로 했던 연구들에서 확인된 것에 비해 매우 적은 비율이라 할 수 있다. 9개의 두 번째 막대들 중 5개는 강한 막대 (SB)안에서 발달해 있고, 4개는 약한 막대 (SAB) 안에 발달해 있어, 수치적으로는 두 번째 막대의 강한 막대와 약한 막대 사이의 선호도 차이는 없어 보인다. 하지만, 약한 막대 안에 발달해 있는 두 번째 막대들은 막대와 서로 다른 방향의 타원 구조만 보이는 반면, 강한 막대 안에 발달해 있는 두번째 막대들은 nuclear ring, nuclear arm등과 함께 더욱 발달된 모습을 보인다. 또한 두 번째 막대를 가지고 있는 8개의 은하 모두에서 주 막대를 따라 중심부로 길게 늘어서 먼지 띠가 뚜렷하게 보이고, 허블 분류에서는 Sab(T=3), Sb (T=4)에 주로 분포해있다.

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서부인도양 해역 다랑어어업의 생태계기반 어업 위험도 평가 (Ecosystem-based Fishery Risk Assessment of Tuna Fisheries in the Western Indian Ocean)

  • 하영신;이성일;권유정
    • 한국수산과학회지
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    • 제56권4호
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    • pp.449-461
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    • 2023
  • The aim of this study was to conduct an ecosystem-based fishery risk assessment of tuna fisheries in the Western Indian Ocean. We selected gillnet, purse seine, hand line, baitboat, and longline fisheries as the target fisheries method, and selected longtail tuna (Thunnus tonggol), narrow-barred Spanish mackerel (Scomberomorus commerson), kawakawa (Euthynnus affinis), skipjack tuna (Katsuwonus pelamis), yellowfin tuna (T. albacares), bigeye tuna (T. obesus), albacore tuna (T. alalunga) and swordfish (Xiphias gladius) as the target species. The risk score for the size at the first capture in sustainability objective was high, especially, for the purse seine and baitboat fisheries using the fish aggregating devices (FADs). The risk score for the bycatch in the biodiversity objective was high for the gillnet fishery, and the gillnet fisheries using FADs showed high risks for the habitat quality objective due to the loss of the fishing gears. With regards to the socio-economic benefits objective, the risk score of the sales profits was low due to high sales of the tuna fisheries. The ecosystem risk score in the Western Indian Ocean was estimated to be moderate, although management is required for some of the indicators that have high-risk scores.

Knowledge Graph of Administrative Codes in Korea: The Case for Improving Data Quality and Interlinking of Public Data

  • Haklae Kim
    • Journal of Information Science Theory and Practice
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    • 제11권3호
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    • pp.43-57
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    • 2023
  • Government codes are created and utilized to streamline and standardize government administrative procedures. They are generally employed in government information systems. Because they are included in open datasets of public data, users must be able to understand them. However, information that can be used to comprehend administrative code is lost during the process of releasing data in the government system, making it difficult for data consumers to grasp the code and limiting the connection or convergence of different datasets that use the same code.This study proposes a way to employ the administrative code produced by the Korean government as a standard in a public data environment on a regular basis. Because consumers of public data are barred from accessing government systems, a means of universal access to administrative code is required. An ontology model is used to represent the administrative code's data structure and meaning, and the full administrative code is built as a knowledge graph. The knowledge graph thus created is used to assess the accuracy and connection of administrative codes in public data. The method proposed in this study has the potential to increase the quality of coded information in public data as well as data connectivity.

Role of Mass Inflow and Supernova Feedback on Nuclear Ring Star Formation

  • Moon, Sanghyuk;Kim, Woong-Tae;Kim, Chang-Goo;Ostriker, Eve C.
    • 천문학회보
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    • 제46권2호
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    • pp.37.1-37.1
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    • 2021
  • Observations suggest the star formation in nuclear rings of barred galaxies proceeds episodically in time and sometimes asymmetrically in space. Existing theories and numerical simulations suggest that the episodic star formation is perhaps due to either supernova feedback combined with fluid instabilities or time-varying mass inflow rate. However, it has been challenging to discern what dominates in shaping the star formation history because the effects of the inflow and feedback are blended in global simulations of nuclear rings. To understand their effects separately, we construct semi-global models of nuclear rings, which treat the mass inflow rate as a model parameter. By running simulations with the inflow rates kept constant or oscillating in time, we find that the star formation rate (SFR) of the rings varies coherently with the inflow rate, while the feedback is responsible only for stochastic fluctuations of the SFR within a factor of two. The feedback instead plays an important role in maintaining the vertical dynamical equilibrium and setting the depletion time. While the asymmetry in the inflow does not necessarily lead to the asymmetry in the star formation, we find that the rings undergo a transient period of lopsided star formation when the inflow rate of only one dust lane is suddenly increased.

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Bar Formation and Enhancement of Star Formation in Disk Galaxies in Interacting Clusters

  • Yoon, Yongmin;Im, Myungshin
    • 천문학회보
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    • 제45권1호
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    • pp.31.1-31.1
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    • 2020
  • A merger or interaction between galaxy clusters is one of the most violent events in the universe. Thus, an interacting cluster is an optimum laboratory to understand how galaxy properties are influenced by a drastic change of the large-scale environment. Here, we present the observational evidence that bars in disk galaxies can form by cluster-cluster interaction and the bar formation is associated with star-formation enhancement. We investigated 105 galaxy clusters at 0.015

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Stellar photometric Properties in the outskirt of NGC 5236

  • Kim, Sanghyun;Kim, Minjin;Byun, Woowon;Sheen, Yun-Kyeong;Ho, Luis C;Lee, Joon Hyeop;Kim, Sang Chul;Jeong, Hyunjin;Park, Byeong-Gon;Seon, Kwang-Il
    • 천문학회보
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    • 제45권1호
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    • pp.60.2-60.2
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    • 2020
  • In the hierarchical framework, galaxies grow through mergers and accretion. Those mechanisms leave faint features, such as stellar streams, shells and smooth stellar halos in the outskirts of galaxies. In order to search for those features in the nearby galaxies, we are conducting a KMTNet Nearby Galaxy Survey using the Korea Microlensing Telescope Network. We present a deep and wide-field imaging of NGC 5236, a barred spiral galaxy. In one-dimensional surface brightness profiles, we reach 28, 29 mag/arcsec2 in the R- and B-band, respectively. We find that the outer disk of NGC 5236 can be well described with a single exponential profile up to 17 kpc (~3.8 Reff) indicating that the excess light due to the stellar halo is not clearly detected. B-R color gradually increases towards the outskirts of the galaxy. It may reveal that stellar properties in the outskirts are marginally distinctive from those in the central part.

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Star formation in nuclear rings controlled by bar-driven gas inflow

  • Moon, Sanghyuk;Kim, Woong-Tae;Kim, Chang-Goo;Ostriker, Eve C.
    • 천문학회보
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    • 제46권1호
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    • pp.51.2-51.2
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    • 2021
  • Nuclear rings are sites of intense star formation at the center of barred spiral galaxies. A straightforward but unanswered question is what controls star formation rate (SFR) in nuclear rings. To understand how the ring SFR is related to mass inflow rate, gas content, and background gravitational field, we run a series of semi-global hydrodynamic simulations of nuclear rings, adopting the TIGRESS framework to handle radiative heating and cooling as well as star formation and supernova feedback. We find: 1) when the mass inflow rate is constant, star formation proceeds in a remarkably steady fashion, without showing any burst-quench behavior suggested in the literature; 2) the steady state SFR has a simple linear relationship with the inflow rate rather than the ring gas mass; 3) the midplane pressure balances the weight of the overlying gas and the SFR surface density is linearly correlated with the midplane pressure, consistent with the self-regulated star formation theory. We suggest that the ring SFR is controlled by the mass inflow rate in the first place, while the gas mass adjusts to the resulting feedback in the course of achieving the vertical dynamical equilibrium.

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Production of Transgenic Chimeric Chickens Using Blastodermal Cells

  • Yan, Haifeng;Lee, Chaeyoung;Xiao, Bingnan;Trefil, Pavel;Liu, Shixun;Kim, Younyoung;Wu, Xiaolin
    • Asian-Australasian Journal of Animal Sciences
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    • 제18권2호
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    • pp.158-164
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    • 2005
  • A practical approach was proposed to produce transgenic chimeric chickens using blastodermal cells (BCs). The chicken BCs were mechanically dissociated and transferred into the recipient eggs that had been exposed to 500 rads irradiation of$^{60}Co$ and windowed on the equatorial plane. Chimeric chickens were generated using two models: the crosses (MXL) from Black Minors (ii,EE,b/b) ♂${\times}$Barred Leghorns (ii,ee,B/-) ♀ as donors and White Leghorns (WL, II) as acceptors (Model 1), or the Black Heifengs (BH, ii,EE,bb) as donors and Hua-xing white (HW, II) as recipients (Model 2). The treated eggs were incubated in their original shells in normal conditions until hatching. Green fluorescent protein (GFP) gene was transferred into the BCs derived from MXL and BH via lipofectamine and the pEGFP-C1, and transfection efficiency into the BCs was examined under a fluorescent microscope. Potential transgenic chimeras were selected based on the proposed methods in this study. Using the fresh BCs, the best rate of phenotypic chimeras was 6.7% and 26.0% in model-1 groups, and model-2 groups, respectively. We also described the optimized conditions for transfection. Although 30% of the BCs transfected in vitro emitted green light under an inverted fluorescent microscope, no embryos injected with the transfected BCs expressed foreign GFP gene at 3-4 days.

안성주택과 중국의 ICSID 중재사건에 관한 사례연구 (Comments on the ICSID Award Ansung Housing v. People's Republic of China)

  • 강병근
    • 한국중재학회지:중재연구
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    • 제27권2호
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    • pp.37-57
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    • 2017
  • On 9 March 2017, a Tribunal constituted under the ICSID Convention issued its ruling in the case of Ansung Housing v. People's Republic of China, dismissing with prejudice all claims made by the Claimant, Ansung Housing Co., Ltd., in its Request for Arbitration, pursuant to ICSID Arbitration Rule 41(5). Ansung Housing v. PRC has drawn attention since it is the first case where an investor with Korean nationality initiated an ICSID arbitration on the basis of the Korea-China Bilateral Investment Treaty (BIT) as amended in 2007 between the Republic of Korea and the People's Republic of China. The Tribunal finds that its ruling is about a lack of jurisdiction of the ICSID and of its own competence as well as regarding manifest lack of legal merit due to a lack of temporal jurisdiction, since a Respondent's Rule 41(5) objection is concerned with the three-year limitation period in Article 9(7) of the Korea-China BIT. The Tribunal held that, under Article 9(7) of the Korea-China BIT, the limitation period begins with an investor's first knowledge of the fact that it has incurred loss or damage, not with the date on which it gains knowledge of the quantum of that loss or damage. Finally, the Tribunal held that Ansung submitted its dispute to ICSID and made its claim for purposes of Article 9(3) and (7) of the BIT after more than three years had elapsed from the date on which Ansung first acquired knowledge of loss or damage and that the claim is time-barred and, as such, is manifestly without legal merit. It remains to be seen whether the aggrieved Claimant initiates annulment proceedings before an ad hoc committee under the ICSID Convention. It is quite interesting to see whether the decisions by the Tribunal should be reversed on the basis of the Claimant's arguments as to the start date as well as the end date of the limitation period under the Korea-China BIT.