• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.42.1-42.1
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• 2013

In the LCDM paradigm, hierarchical merging is thought to play a key role in the formation and evolution of massive galaxies. Theoretical and observational studies suggest that massive galaxies started forming at high redshifts and were assembled via numerous mergers. Galaxy clusters are the sites where the most massive galaxies are found and the most dramatic merger histories are embedded. The previous work of Sheen et al. (2012) identified via visual inspection many massive galaxies with merger features in clusters, which surprised the community. In this study we aim to quantify peculiarity of galaxies to pin down the merger frequency in cluster environments more objectively. We have performed optical deep imaging of 4 Abell clusters by using IMACS f/2 on a Magellan Badde 6.5-m telescope. For the galaxies in our data, we applied GALFIT algorithm, which fits analytic models to galaxy data, and we analyzed their residuals. We present the preliminary results of our sample galaxies.

• Information Systems Review
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• v.19 no.4
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• pp.171-182
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• 2017

Although economic growth has been retarded since the global economic crisis over recent decades, a large number of firms consider mergers and acquisitions (M and A) as a strategy to survive in a highly competitive market. In particular, an increasing number of firms pursue M and A with IT firms in recent years. In this study, we analyze the post-merger risks measured as ROA volatility for acquiring firms when they seek to acquire an IT firm. Our analysis suggests that a firm with prior experience in M and A acquires IT firms aggressively. Moreover, a substantial number of IT firms are relatively small and unlisted when they are acquired. We also show that an acquiring firm's post-merger risk (i.e., ROA volatility) increases after its acquisition of IT firms. However, an increase in post-merger risk is alleviated when relatedness exists between an acquiring firm and target.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.34.3-35
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• 2016

Ram pressure stripping of early-type galaxies has been largely neglected until now because of their gas poor nature. MUSE IFU observation vividly reveal the presence of star-forming blobs and ionised gas tails, around an early-type galaxy in Abell 2670. The galaxy was identified as a post-merger galaxy with disturbed faint features, in MOSAIC 2 deep optical images. The imaging also revealed a series of star-forming blobs, situated in the direction facing away from the cluster centre. Thanks to the revolutionary wide field-of-view of the MUSE, combined with 8.2-m VLT (UT-4) at Cerro Paranal, we could simultaneously obtain IFU spectra of the blobs, as well as the galaxy. The MUSE spectra clearly confirms that the star-forming blobs are associated with the early-type galaxy. Moreover, MUSE reveals long ionised-gas tails, emanating from the galaxy. The quantity of gas indicates a gas rich progenitor has merged with the early-type galaxy. However the direction of the tails and blobs, and the blob morphology, appears to indicate that strong ram-pressure stripping may have stripped out gas brought in by the merger. We will present kinematic structure of the whole system (the galaxy, star-forming blobs, and gas tails), as well as the star formation history of the system, supporting a scenario where a recent galaxy merger is subjected to cluster environmental mechanisms.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.60.3-61
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• 2016

Galaxy morphology involves complex effects from both secular and non-secular evolution of galaxies. Although it is a final product of galaxy evolution, it gives a clue to the processes that the a galaxy has gone through. Galaxy clusters are the sites where the most massive galaxies are found, and thus the most dramatic merger histories are embedded. Our deep imaging program (${\mu}{\sim}28\;mag\;arcsec^{-2}$), KASI-Yonsei Deep Imaging Survey for Clusters (KYDISC), targets 14 Abell clusters at z = 0.016 - 0.14 using IMACS/Magellan telescope and MegaCam/CFHT to investigate cluster galaxies especially on low surface brightness features related to galaxy interactions. We visually classify galaxy morphology based on criteria related to secular or merger related evolution and find that the morphological mixture of galaxies varies considerably from cluster to cluster. Moreover it depends on the characteristics (e.g. cluster mass) of cluster itself which implies that environmental effects in cluster scale is also an important factor to the evolution of galaxies together with intrinsic (secular) and galaxy merger. Our deep imaging survey for morphological inspection of cluster galaxies with low surface brightness is expected to be a useful basis to understand the nature of cluster galaxies and their internal/external evolutionary path.

• Phonetics and Speech Sciences
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• v.5 no.2
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• pp.25-31
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• 2013

This study examined cross-generational changes in the vowel system of Seoul Korean. Acoustic analyses of the vowel formants of /o/ and /u/, and their Euclidean distances in the vowel space were undertaken to explore an on-going merger of these two vowels as proposed in previous acoustic studies and a phonological analysis by Chae (1999). A robust cross-generational change of /o/ and /u/ was found, more evident for female speakers than for male speakers. For female speakers, with each successive generation, /o/ became increasingly approximated with /u/, regardless of the syllable positions that the target vowels were posited, whereas the cross-generational differences in the Euclidean distances were only shown in the second syllable position for the male speakers. These results demonstrate that 1) women are more advanced than men in the on-going approximation of /o/ and /u/; 2) the approximation of /o/ and /u/ is common in the non-initial position. Taken together, the merger of /o/ and /u/ appears to be in progress in Seoul Korean.

• Asia-Pacific Journal of Business
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• v.11 no.2
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• pp.173-188
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• 2020

Purpose - This study examines the determinants of offer price and short-term and long-term performance of small and medium-sized enterprise(SME) IPO stocks listed on the KOSDAQ during the period from July 2007 to December 2016. Design/methodology/approach - The SME IPO samples are classified into three categories of regular listing, technology-based special listing, and listing by merger with special purpose acquisition company(SPAC), whose results are compared each other and compared to the result for the KOSDAQ listing of large firms. Findings - From the point of SME management which attempts to list its company on the KOSDAQ, the listing by merger with SPAC is the most unfavorable, and the underpricing phenomenon of the technology-based special listing is severe in the second place. By contrast, IPO stock investors can earn the largest abnormal return by purchasing the SPAC which succeeds the merger with unlisted firm, and the next abnormal returns are obtained in the order of the IPO stocks of technology-based special listing, regular listing of SMEs, and regular listing of large firms. However, it is interesting to observe that the net buying ratio of individual investors is relatively large for the IPO stocks of regular listing of SMEs and large firms, which exhibit the long-term under-performance. Research implications or Originality - This result implies that the exceptional listing system such as the technology-based special listing or the listing by merger with SPAC cost the SMEs which bypass the complicated procedure of the regular listing.

• Analyses & Alternatives
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• v.1 no.2
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• pp.2-12
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• 2017

Research on democratic transitions has relatively ignored the question of why some countries experience a regressive form of political pacts, while others do not. This paper develops a simple game-theoretic model to explain the phenomenon of collusive pacts in the process of democratization. Trasformismo is a term that refers to a system of political exchange based on informal clientelistic politics. The existing studies of the politics of trasformismo have emphasized the timing of industrialization and the tradition of strong state as conditions of the politics of trasformismo. However, not every late industrializers and not every strong states experienced some variants of collusive political pacts in their trajectories of democratization. In this paper, I contend that the politics of trasformismo is rather a generalizable pattern of political elites' behavior under particular circumstances. By developing a simple game theoretic model, this paper suggests the conditions under which political actors are likely to collude to a regressive form of political pacts. The model shows that the likelihood of collusion to a regressive form of political pacts is a function of a set of parameters. First, a higher level of incumbency advantage in electoral competition is likely to be associated with a higher probability of collusive political pacts. Second, a higher degree of the monopoly of political representation of political parties without a close link with a variety of societal forces is likely to induce collusive behavior among politicians. Third, the ruling party leader's expectations about the likelihood of a safe extrication are related to collusive political pacts. This paper then engages in a case study of the 1990 three-party merger in South Korea. The 1990 Korean case is interesting in that the ruling party created a new party after having merged with two opposition parties. This case can be considered a result of political maneuver in a context of democratization. The case study suggests the empirical relevance of the game-theoretic model. As the game of trasformismo and the case study of the 1990 three-party merger in South Korea have shown, the collusive political pact was neither determined by a certain stage of economic development nor by a particular cultural systems. Rather, it was a product of the art of trasformismo based on party leaders' rational calculations of the expected likelihood of taking governing power.

• Proceedings of the Korean Society for Language and Information Conference
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• 1994.02a
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• pp.213-222
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• 1994

• 대학교육
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• s.128
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• pp.105-108
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• 2004

• Journal of IKEEE
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• v.25 no.3
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• pp.425-429
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• 2021

Vehicle platooning in automated connected vehicle systems is an efficient transportation operation model that not only significantly reduces computational load and networking overhead of the central system but also improves traffic flow. For efficient platoon group management, it is important to maintain the platoon group size appropriately and to control the merge request of a new vehicle and other group member vehicle. In this paper, we present a merger control scheme that accepts or rejects merge requests based on the current group size and the priority of vehicles. The proposed method was analyzed and validated through mathematical models based on Markov chains. Performance evaluation shows that the proposed scheme properly manages the load of the central system.