• 대한수학회논문집
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• 제19권4호
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• pp.745-757
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• 2004

The Reidemeister orbit set plays a crucial role in the Nielsen type theory of periodic orbits, much as the Reidemeister set does in Nielsen fixed point theory. Let f : G $\longrightarrow$ G be an endomorphism between the fundamental group of the mapping torus. Extending Jiang and Ferrario's works on Reidemeister sets, we obtain algebraic results such as addition formulae for Reidemeister orbit sets of f relative to Reidemeister sets on suspension groups. In particular, if f is an automorphism, an similar formula for Reidemeister orbit sets of f relative to Reidemeister sets on given groups is also proved.

• 정보처리학회논문지A
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• 제8A권3호
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• pp.245-252
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• 2001

멀티컴퓨터 시스템은 많은 연산 노드들을 이용함으로써 높은 성능을 얻는다. 다차원 매쉬(mash)는 단순함과 효율성 때문에 멀티컴퓨터 구조로 널리 이용되었다. 본 논문은 3차원 토러스(torus) 시스템을 위한 최초 적합(first-fit) 방법에 기반한 효율적인 프로세서 할당 알고리즘을 제안한다. 이 알고리즘은 CST(Coverage Status Table)을 이용하여 3차원 정보를 2차원 정보로 변형하므로써 프로세서 할당 시간을 최소화 한다. 종합적인 컴퓨터 시뮬레이션 결과는 제안한 방법이 최적 적합(best-fit)에 기반한 기존 방법들과 비교해서 프로세서 이용률은 비슷하면서, 프로세서 할당 시간이 항상 짧다는 것을 보여준다. 성능 차이는 입력 부하가 증가함에 따라 더욱 두드러진다. 다른 스케줄링 환경상에서 제안된 방법의 성능을 조사하기 위해서, 전형적인 FCFS 스케줄링 기법과 함께 non-FCFS 스케줄링 기법도 연구된다.

• 천문학회지
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• 제54권2호
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• pp.37-47
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• 2021

Reverberation mapping (RM) is an efficient method to investigate the physical sizes of the broad line region (BLR) and dusty torus in an active galactic nucleus (AGN). The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) mission will provide multi-epoch spectroscopic data at optical and near-infrared wavelengths. These data can be used for RM experiments with bright AGNs. We present results of a feasibility test using SPHEREx data in the SPHEREx deep regions for torus RM measurements. We investigate the physical properties of bright AGNs in the SPHEREx deep field. Based on this information, we compute the efficiency of detecting torus time lags in simulated light curves. We demonstrate that, in combination with complementary optical data with a depth of ~ 20 mag in B-band, lags of ≤ 750 days for tori can be measured for more than ~ 200 bright AGNs. If high signal-to-noise ratio photometric data with a depth of ~ 21-22 mag are available, RM measurements are possible for up to ~ 900 objects. When complemented by well-designed early optical observations, SPHEREx can provide a unique dataset for studies of the physical properties of dusty tori in bright AGNs.

• 천문학회지
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• 제38권2호
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• pp.183-186
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• 2005

We present results of the VLBA observation toward the radio continuum and water maser emissions in a nearby LINER galaxy NGC 1052. The jet structure observed in 2000 is similar to that in 1998, and the two jet structures in 1998 and 2000 support the sub-luminal motion with apparent velocity of 0.26c. Distribution of water maser spots are located ${\~}$0.05 pc shifted to southwest from the component which is supported to be the nucleus, and no rapid positional change of the water maser gas with respect to the central engine is seen from 1995 to 2000. The maser gas is positionally coincident with a plasma torus, and the position of the maser gas relative to the nucleus is stable from 1995 to 2000. The maser gas in NGC 1052 could be explained to be associated with the nuclear circumnuclear torus or disk like the situation found in the nucleus of NGC 4258.

• 천문학회보
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• 제40권2호
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• pp.48.1-48.1
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• 2015

Active galactic nuclei (AGNs) are powered by a supermassive black hole with an accretion disk and exhibit prominent broad and narrow emission lines. The unification model AGNs requires the presence of a geometrically and optically thick torus component that hides the broad line region from observers lying in the equatorial direction. The strong far UV radiation characterizing AGN spectra is expected to be scattered inelastically in the torus region to reappear around hydrogen Balmer lines or Paschen lines in the form of broad wings. Adopting a Monte Carlo technique we produce broad wings around $H{\alpha}$, $H{\beta}$ and $Pa{\alpha}$ that are formed through Raman scattering. The widths of the wings are mainly affected by the neutral column density of the torus, and the overall strengths are primarily determined by the covering factor and the column density of the neutral region. It is concluded that deep spectroscopy of AGNs of broad wings around hydrogen emission lines may shed much light on the AGN unification model.

• 천문학회보
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• 제39권2호
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• pp.97.1-97.1
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• 2014

We clarify the dynamics connecting a solar flare and a coronal mass ejection (CME) based on the results of a magnetohydrodynamic (MHD) simulation starting from a nonlinear force-free field (NLFFF) in Inoue et al. 2014. In previous studies, many authors proposed numerous candidates for triggering processes of a solar flare and the associated CME. Among them, the tether-cutting reconnection or the torus instability has been supported by recent simulations and observations. On the other hand, our MHD simulation in accordance with more realistic situations show that highly twisted field lines are first produced through a tether-cutting reconnection between the twisted field lines in the NLFFF, and then the newly formed, strongly twisted field erupts away from the solar surface because of a loss of equilibrium. This dynamics corresponds to the onset of a solar flare. Furthermore we have found that the strongly twisted erupting field reconnect with the weakly twisted ambient field during the eruption, creating a large flux tube, and then it rises over a critical height of the torus instability to trigger a CME. From these results, we conclude that the coupled process of tether-cutting reconnection and torus instability is important in the flare-CME relationship.

• 대한수학회논문집
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• 제37권4호
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• pp.1221-1248
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• 2022

In this paper we study the theory of knotoids and braidoids and the theory of pseudo knotoids and pseudo braidoids on the torus T. In particular, we introduce the notion of mixed knotoids in S², that generalizes the notion of mixed links in S³, and we present an isotopy theorem for mixed knotoids. We then generalize the Kauffman bracket polynomial, <; >, for mixed knotoids and we present a state sum formula for <; >. We also introduce the notion of mixed pseudo knotoids, that is, multi-knotoids on two components with some missing crossing information. More precisely, we present an isotopy theorem for mixed pseudo knotoids and we extend the Kauffman bracket polynomial for pseudo mixed knotoids. Finally, we introduce the theories of mixed braidoids and mixed pseudo braidoids as counterpart theories of mixed knotoids and mixed pseudo knotoids, respectively. With the use of the L-moves, that we also introduce here for mixed braidoid equivalence, we formulate and prove the analogue of the Alexander and the Markov theorems for mixed knotoids. We also formulate and prove the analogue of the Alexander theorem for mixed pseudo knotoids.

• 대한치과의사협회지
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• 제25권10호통권221호
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• pp.904-904
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• 1987

• 대한수학회지
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• 제44권5호
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• pp.1079-1092
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• 2007

This paper studies the deformation theory of a holomorphic surjective map from a normal compact complex space X to a compact $K\"{a}hler$ manifold Y. We will show that when the target has non-negative Kodaira dimension, all deformations of surjective holomorphic maps $X{\rightarrow}Y$ come from automorphisms of an unramified covering of Y and the underlying reduced varieties of associated components of Hol(X, Y) are complex tori. Under the additional assumption that Y is projective algebraic, this was proved in [7]. The proof in [7] uses the algebraicity in an essential way and cannot be generalized directly to the $K\"{a}hler$ setting. A new ingredient here is a careful study of the infinitesimal deformation of orbits of an action of a complex torus. This study, combined with the result for the algebraic case, gives the proof for the $K\"{a}hler$ setting.

• 대한수학회지
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• 제52권2호
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• pp.269-331
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• 2015

For a fixed positive integer g, we let $\mathcal{P}_g=\{Y{\in}\mathbb{R}^{(g,g)}{\mid}Y=^tY&gt;0\}$ be the open convex cone in the Euclidean space $\mathbb{R}^{g(g+1)/2}$. Then the general linear group GL(g, $\mathbb{R}$) acts naturally on $\mathcal{P}_g$ by $A{\star}Y=AY^tA(A{\in}GL(g,\mathbb{R}),\;Y{\in}\mathcal{P}_g)$. We introduce a notion of polarized real tori. We show that the open cone $\mathcal{P}_g$ parametrizes principally polarized real tori of dimension g and that the Minkowski modular space 𝔗g = $GL(g,\mathbb{Z}){\backslash}\mathcal{P}_g$ may be regarded as a moduli space of principally polarized real tori of dimension g. We also study smooth line bundles on a polarized real torus by relating them to holomorphic line bundles on its associated polarized real abelian variety.