• 천문학회보
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• 제44권1호
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• pp.46.2-46.2
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• 2019

We propose a deep learning model that can generate a waveform of coalescing binary black holes in merging and ring-down phases in less than one second with a graphics processing unit (GPU) as an approximant of gravitational waveforms. Up to date, numerical relativity has been accepted as the most adequate tool for the accurate prediction of merger phase of waveform, but it is known that it typically requires huge amount of computational costs. We present our method can generate the waveform with ~98% matching to that of the status-of-the-art waveform approximant, effective-one-body model calibrated to numerical relativity simulation and the time for the generation of ~1500 waveforms takes O(1) seconds. The validity of our model is also tested through the recovery of signal-to-noise ratio and the recovery of waveform parameters by injecting the generated waveforms into a public open noise data produced by LIGO. Our model is readily extendable to incorporate additional physics such as higher harmonics modes of the ring-down phase and eccentric encounters, since it only requires sufficient number of training data from numerical relativity simulations.

• The Journal of Asian Finance, Economics and Business
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• 제9권5호
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• pp.99-109
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• 2022

The main reason for the increase in cross-border mergers and acquisitions in developed and emerging countries is globalization and growing economic interdependence across countries. The state of the economy has a significant impact on whether cross-border mergers and acquisitions are encouraged or discouraged by international strategic capital market changes. This study empirically evaluates the influence of determinants of economic development on the scale effect of Cross Border M&As separately on emerging and developed nations as a research gap. We first separated the small and large scale firms based on companies' worth and used panel regression to analyze the impact of GDP, employment rate, and market capitalization on cross-border merger & acquisition deals over the period of 2008-2018. Results indicate that GDP and market capitalization have a positive effect on CBM&A, whereas employment rate has a negative effect on CBM&A deals in large-scale firms of both emerging and developed countries. This study results offer the implication for the potential investors and policymakers to strategically analyze the implementation of cross-border mergers & acquisitions.

• 천문학회보
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• 제46권1호
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• pp.28.1-28.1
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• 2021

We present a statistical analysis of dark matter halos with interacting neighbors using a set of cosmological simulations. We classify the neighbors into two groups based on the total energy (E₁₂) of the target-neighbor system; flybying neighbors (E₁₂ ≥ 0) and merging ones (E₁₂ < 0). First, we find a different trend between the flyby and merger fractions in terms of the halo mass and large-scale density. The flyby fraction highly depends on the halo mass and environment, while the merger fraction show little dependence. Second, we measure the spin-orbit alignment, which is the angular alignment between the spin of a target halo (${\vec{S}}$ ) and the orbital angular momentum of its neighbor (${\vec{L}}$). In the spin-orbit angle distribution, the flybying neighbors show a weaker prograde alignment with their target halos than the merging neighbors do. With respect to the nearest filament, the flybying neighbor has a behavior different from that of the merging neighbor. Finally, we discuss the physical origin of two interaction types.

• 인터넷정보학회논문지
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• 제22권4호
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• pp.123-134
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• 2021

본 논문은 넷플릭스와 SK브로드밴드 소송의 핵심 쟁점인 인터넷의 유상성에 관해 논증하고 있다. 인터넷 연결 관련 당사자 간 기밀유지협약이 일반적인 시장의 특성으로 인해 거래 데이터 수집 한계가 있어 연구방법론으로 사례연구 및 판례분석을 채택하였다. 즉 CP를 중심으로 한 일부에서 인터넷은 무료로 고안된 망이기 때문에, 그리고 시장에서 무료로 이용하고 있는 경우가 많으므로 ISP가 CP를 포함한 이용자들에게 요금을 부과할 권리가 없다고 하는 주장에 대해 인터넷이 무료가 아님을 미국 인터넷 역사와 2016년 Charter 합병 관련 소송 분석 등 두 가지 접근방법을 통해 검토한다. 첫째, 미국 인터넷의 시작이라 알려진 ARPANET부터 백본 상용화까지의 초기 인터넷 망을 고안할 당시 인터넷의 무상성은 고려되거나 시행된 바가 없으며 NSFNET 백본의 망 운영비 확보를 위해 연방정부가 지원금을 부담하거나 기관들이 요금을 부담하고 있었다. 인터넷 초기에도 인터넷망 이용에 따른 대가 지불이 있었다. 더불어 Free Peering의 free는 무상이 아니라 물물교환(Barter)을 의미한다. 둘째, 미국 연방정부 행정명령서 및 법원의 판결문과 같은 공문서를 분석하여 인터넷의 유상성을 입증하고 있다. 2016년 미 CATV 사업자 차터(Charter)의 합병승인 조건 명령서와 동 명령 관련한 소송 판결문에서 현재 미국 인터넷 시장 내 ISP-CP(OTT 포함) 간 유료 정산을 하고 있으며, 망 이용대가와 망 중립성 규제는 무관하다는 점을 공식적으로 확인할 수 있었다. 결론적으로 인터넷의 기술적 특성, 망 구조, 망 운용, 제도 측면에서 인터넷이 무료인 적은 없음을 논증하고 있으며 국내 정책 및 규제 차원에서 제도 개선을 제안하고 있다.

• 천문학회지
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• 제37권5호
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• pp.299-305
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• 2004

We find evidence of a hard X-ray excess above the thermal emission in two cool clusters (Abell 1750 and IC 1262) and a soft excess in two hot clusters (Abell 754 and Abell 2163). Our modeling shows that the excess components in Abell 1750, IC 1262, and Abell 2163 are best fit by a steep power law indicative of a significant non-thermal component. In the case of Abell 754, the excess emission is thermal, 1 ke V emission. We analyze the dynamical state of each cluster and find evidence of an ongoing or recent merger in all four clusters. In the case of Abell 2163, the detected, steep spectrum, non-thermal X-ray emission is shown to be associated with the weak merger shock seen in the temperature map. However, this shock is not able to produce the flatter spectrum radio halo which we attribute to post-shock turbulence. In Abell 1750 and IC 1262, the shocked gas appears to be spatially correlated with non-thermal emission suggesting cosmic-ray acceleration at the shock front.

• 유통과학연구
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• 제11권9호
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• pp.25-29
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• 2013

Purpose - This study aimed to examine how the integration of IT systems was applied in the merger and acquisition (M&A) process in a Korean retail industry, based on the conceptual framework of a combination of related, existing literature. Research design, data, methodology - We employed the case study method, which involved literature reviews and interviews. We conducted a documentary survey and interviews regarding the M&A case for company A. Results - Company A had an integration strategy and plan with IT expertise before it began integrating both IT systems in D-Day. The IT integration of both systems was completed efficiently and effectively. Company A utilized not just one but all integration options, which was done in stages and according to situation. Conclusions - Companies should develop an integration strategy and have a clear integration plan with IT expertise in order to achieve successful integration. Companies trying to integrate IT systems during an M&A process can utilize all integration options in consideration of their business context and IT system conditions.

• 천문학회보
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• 제41권1호
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• pp.66.2-66.2
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• 2016

Red quasars have been suspected to be an intermediate population between merger-driven star-forming galaxies and normal quasars. In this scenario, red quasars are expected to have dusty red color coming from the dust extinction by dust and gas in their host galaxy. However, several studies have proposed different explanation of the red color of red quasars, which are i) a moderate viewing angle between type 1 and 2 quasars, ii) an unusual covering factor of dust torus, and iii) an anomalous synchrotron emission with a peak at NIR wavelength. In this study, we investigate the factor leading to the red color of red quasars by using the line luminosity ratios of the hydrogen Balmer to Paschen series of 11 red quasars. We find the Pb/Hb luminosity ratios of the red quasars are significantly higher than those of normal quasars. Moreover, we compare the Pb/Hb luminosity ratios of the red quasars to the theoretically expected line luminosity ratios computed from the CLOUDY code. We find the line luminosity ratios of the red quasars cannot be explained by the theoretical line luminosity ratios with any physical conditions. We conclude that red color of red quasars comes from dust extinction by their host galaxy. This result is consistent with the picture that red quasars are an intermediate population between the merger-driven star-forming galaxies and normal quasars.

• 천문학회보
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• 제37권2호
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• pp.90.2-90.2
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• 2012

Galaxy merging plays a important role to the formation and evolution of galaxy. Early-type galaxies are believed to be formed by galaxy merging. We combined 3 color images in g,r,i band using Stripe82 image of which the surface brightness is 2 mag deeper than that of SDSS image. We classified early-type galaxies which have the merging features, the evidence of galaxy mergers through careful visual inspection. We investigated the IR properties of early-type galaxies with the merging feature using WISE data. We analyzed the star formation according to the type of galaxy. Early-type galaxies with the merging feature show the higher star formation than non-merging galaxies, but the difference is not significant. This results implies that quite a few early-type galaxies might be formed by dry merger, not wet merger. Meanwhile, the most of ULIRGs show tidal tail, on the other hand, early-type galaxies show tidal tail including shell structure. It suggests that ULIRGs have more gas and it might be in early stage of galaxy merging, early-type galaxies might be in the late stage of galaxy merging.

• 아태비즈니스연구
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• 제11권3호
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• pp.1-20
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• 2020

Purpose - This paper shows an unexplored area related to involuntary delisting. Specifically, this research investigates the effect of target firm information asymmetry on the likelihood that the acquirer or newly merged firm will be forcibly delisted post-merger. Design/methodology/approach - The research uses a sample gathered on local US mergers and acquisitions from the Thomson Reuters Securities Data Company (SDC) Platinum Mergers and Acquisitions database. It applies the logistic regression with industry and year effects and corrects the error term using clustering at the industry level. The research also matches the forced delisted firms to control firms based on industry, acquisition completion year, and firm size and then employs a matched sample analysis. Findings - Findings show that M&As between firms where the target firm is opaque and burdened with high information asymmetry issues are likely to be paid for using majority stock and that M&As involving such opaque targets also have a higher likelihood of getting delisted post-merger. Research implications or Originality - Our results are relevant given the very nature of M&As which involve two players: the acquirer and target who both may have different incentives. Acquirers especially have the tendency to suffer losses and even get delisted if they over-pay for or get merged to a poor target which conceals its poor performance evidenced by higher accruals quality.

• 인문언어
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• 제8집
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• pp.313-329
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• 2006

In some American English dialects, the vowels /a:/ or /c:/ have been replaced with /a:/, as in caught /ka:t/ dog /da:g/ that were pronounced in /kc:t/, and /dc:g/ previously. General American does not have /a:/ in its vowel system. But in East American and Western Pensylvania, cot and caught are homophones, /ka:t/, and similarly with other pairs such as collar vs. caller, stock vs. stalk, don vs. down, knotty vs. naughty. The use of /a/ or /c/ is quite unstable, and is a well-known diagnostic for distinguishing the northern speech area of the United States from the midland and southern area. For an increasing number of Americans, however, entirely lack the opposition between /a/ and /c/, merging to /a/, referring to 'both' of the vowels of lot. This paper investigates the use of /b:/ in American dialects and its relationship with /a:/, /c:/ in AE, and with short /a/ in RP. Examining the isoglosses of the use of /a:/ in various databases of the phonological atlas of North America, this paper discusses the use, position, and trend of merger to /a:/ from the vowels of /a:/ and /c:/ in Current American English.