• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.35.1-35.1
• /
• 2019

We present a statistical analysis on the spin-orbit alignment of dark matter halo pairs in cosmological simulations. The alignment is defined as the angular concurrence between the halo spin vector (${\vec{S}}$) and the orbital angular momentum vector (${\vec{L}}$) of the major companion. We identify interacting halo pairs with the mass ratios from 1:1 to 1:3, with the halo masses of 10.8 < $Log(M_{halo}/M_{sun}$) < 13.0, and with the separations smaller than a sum of their virial radii ($R_{12}<R_{1,vir}+R_{2,vir}$). Based on the total energy ($E_{12}$), the pairs are classified into flybys ($E_{12}$ > 0) and mergers ($E_{12}{\leq}0$). By measuring the angle (${\theta}_{SL}$) between ${\vec{S}}$ and ${\vec{L}}$, we confirm a strong spin-orbit alignment signal such that the halo spin is preferentially aligned with the orbital angular momentum of the major companion. We find that the signal of the spin-orbit alignment for the flyby is weaker than that for the merger. We also find an unexpected excess signal of the spin-orbit alignment at $cos{\theta}_{SL}{\sim}0.25$. Both the strength of the spin-orbit alignment and the degree of the excess depend only on the environment. We conclude that the halo spin is determined by the accretion in a preferred direction set by the ambient environment.

• The Bulletin of The Korean Astronomical Society
• /
• v.45 no.1
• /
• pp.31.1-31.1
• /
• 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

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.1
• /
• pp.54.3-54.3
• /
• 2021

The Coma cluster serves as an ideal laboratory to study the cluster assembly history. It is known as a typical example of relaxed galaxy clusters. However, recent X-ray, radio and optical observations revealed a number of substructures in Coma. The NGC 4839 group is an interesting substucture in the sense that it is overlappled with the X-ray bright component in the south-west region. Recent hydrodynamical simulations in the literature suggest that the NGC 4839 group came from the north-east direction of Coma, passed the apocenter about 1 Gyr ago, and started a second infall to the Coma core recently. Interestingly a number of E+A galaxies are located along the filament connecting the NGC 4839 group and the Coma core. We are surveying a wide area covering the NGC 4839 group to search for globular clusters and use them to investigate any connection between the globular clusters and the merger scenario of the NGC 4839 group. We utilized Subaru Hyper Suprime-Cam archival images of two circular fields with diameter ~1.8 deg, covering the Coma core and the NGC 4839 group. We discuss the results with regard to the formation history of the NGC 4839 group.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.46 no.3
• /
• pp.101-108
• /
• 2023

Although the proportion of coal-fired power generation is decreasing, efficient operating technology is needed to continuously invest in facilities and reduce maintenance costs until it is abolished. Boilers, one of the main facilities of power plants, operate for a long time in harsh environments of high temperature and high pressure. In addition, damage due to deterioration is likely to occur depending on the fuel and tube material used. It is very important to judge soundness because damage caused by deterioration adversely affects facility operation. Previously, replication method was used to analyze the progress of deterioration. In the replication method, pre-treatment such as chemical treatment is performed on the boiler tube in the field, the area is reproduced by attaching a film, and the replicated film is determined by an expert in the laboratory with an expensive microscope. However, this method involves substantial costs and time requirements, as well as the possibility of human errors. To address these issues, we developed a mobile health assessment system in this research. Since it is detachable and takes images in real time, this system enables swift evaluations across a broad range and facilitates the assessment of preprocessing quality. In addition, it was intended to reduce existing human mistakes by developing a degradation classification algorithm using the merger cluster method.

• Journal of Practical Engineering Education
• /
• v.15 no.3
• /
• pp.589-595
• /
• 2023

Artificial intelligence(AI) is spurring advancements in EdTech, the merger of technology and education. This includes the creation of effective learning materials and personalized student experiences. Our study focuses on developing a programming education software that employs state-of-the-art generative AI. Our software also includes prompts optimized for programming code analysis, which are based on the well-known ChatGPT API. Furthermore, the necessary functions for acquiring programming skills were created with a user interface and developed as a question-and-answer template function based on an AI chatbot. The objective of this study is to guide the development of educational programmes that make use of generative AI.

• Proceedings of the Technology Innovation Conference
• /
• 1996.12a
• /
• pp.196-238
• /
• 1996

Because global innovation-based competition is increasing and the amount of R&D expenditures becomes severely large, it is more likely that mergers and collaborative ventures tend to affect adversely to R&D competition Against this trend, enforcing agency of advanced countries including U.S.A are reassessing certain aspects of competition policy toward mergers and acquisition to ensure that procompetitive, efficiency-enhancing transactions are permitted. The role of competition policy is developing and appropriating new technology and protects the risks involved in the licensing contract of technologies. The role of intellectual property rights is also contrived to promote technological innovation and to increase consumer welfare. That is to say, dynamic efficiency of intellectual property rights includes (l) increase in social welfare and (2) promotion of growth by improvement of quality through invention and commercialization of new product as well as enhanced productive efficiency thorough appropriating new process. Because intellectual property rights are licensed to make use of complementary inputs, the rule of reason approach seems proper when applying antitrust law. To analyze the "Antitrust Guidelines for the Licensing and Acquisition of Intellectual Property"by DOJ and FTC in U.S.A, the author surveyed pros and cons on innovation market approach. This approach will only be used in a narrow range of situations when the evidence is solid, concentration numbers are extremely high, and the agencies can predict with a high degree of certainty that the merger will likely lead either to a slowing in the pace of innovation or the loss of an alternative research track that is likely to lead to a product beneficial to consumers. The author introduces the studies on licensing contract of intellectual property rights and competition polices on behalf of potential inquirers. Also the author invites the interdisciplinary researchers to analyze further with a model on the aspects of the "Notice 1995-10 for Types and Criteria on Unfair Transaction Behavior in International Contracts" by Fair Trade Committee of Korea.

• Phonetics and Speech Sciences
• /
• v.4 no.3
• /
• pp.31-41
• /
• 2012

Recent studies have shown that the stop system of Korean is undergoing a sound change in terms of the two acoustic parameters, voice onset time (VOT) and fundamental frequency (f0). Because of a VOT merger of a consonantal opposition and onset-f0 interaction, the relative importance of the two parameters has been changing in Korean where f0 is a primary cue and VOT is a secondary cue in distinguishing lax from aspirated stops in speech production as well as perception. In English, however, VOT is a primary cue and f0 is a secondary cue in contrasting voiced and voiceless stops. This study examines how Korean English learners use the two acoustic parameters of L1 in producing L2 English stops and whether the sound change of acoustic parameters in L1 affects L2 speech production. The data were collected from six adult Korean English learners. Results show that Korean English learners use not only VOT but also f0 to contrast L2 voiced and voiceless stops. However, unlike VOT variations among speakers, the magnitude effect of onset consonants on f0 in L2 English was steady and robust, indicating that f0 also plays an important role in contrasting the [voice] contrast in L2 English. The results suggest that the important role of f0 in contrasting lax and aspirated stops in L1 Korean is transferred to the contrast of voiced and voiceless stops in L2 English. The results imply that, for Korean English learners, f0 rather than VOT will play an important perceptual cue in contrasting voiced and voiceless stops in L2 English.

• KDI Journal of Economic Policy
• /
• v.27 no.1
• /
• pp.39-79
• /
• 2005

This paper addresses the question of whether a monopolistic banking system can lead to a higher steady state level of capital stock. Information externality has enhanced as the advance of the financial system such as the establishment of the credit bureau system, networking, etc. Hence this paper aims to analyze the effects of both information externality and economic development on the determination of the optimal banking market structure. This paper shows that the presence of information externality together with asymmetric information would explain how a monopoly bank leads to a higher steady state level of capital stock. It also shows that not only under-developed countries but industrialized countries may also benefit from a concentrated banking system. This analysis provides an alternative explanation of the recent deregulation and resulting trends in mergers and acquisitions. This also provides a theoretical foundation to support governments' policy changes toward promoting merger and acquisition activities.

• Journal of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.157-160
• /
• 2005

To constrain the values of the model parameters for the cosmological models involving the time-decaying $\Lambda$ term, we have computed sets of theoretical predictions for the N-m relation of galaxies as well as the CMB angular power spectrum: three types of variation, viz., ${\Lambda}{\propto} T^{-1},\;a^{-m}$, and $H^n$ are thereby assumed following Overduin & Cooperstock (1998), although we concentrate here on the discussion of the results obtained from the first type. Our results for the N-m relation indicate that the observed excess of the galaxy counts N in the faint region beyond the blue apparent magnitude 24 can be reasonably well accounted for with the value of ${\iota}$ in the range between 0.2 and 1. Furthermore, a comparison of our computational results of the CMB spectra with the observational data shows that the models with a mild degree of the $\Lambda$ term decay, viz., with the value of ${\iota}{\le}$0.4, are favorable. In this case, the age of our universe turns out to be larger than or equal to 14 Gyr, the lower limit inferred from some Uranium datings.

• Archives of design research
• /
• v.19 no.1 s.63
• /
• pp.163-170
• /
• 2006

Recently automotive markets are on the way into maturing status with the mega merger between makers which brought equalizations of technology and upgrade of overall performance of vehicles. For the reason why it is the recent trend which has more importance on the software oriented element such as the style design of vehicles than the hardware such as the mechanical elements. This changing characteristics of automotive design which requires more creativity and finished style treatment on an automotive design demand the specific method of designing from the lingual concept of the vehicle. In this research the possibility has been observed the design elements between the greenhouse of the vehicle body with analyzing the shape elements of it and the change of the characteristics of body shape had been observed. The possibility of extract of creating the method of specifying the shape from the lingual concept had been examined either.