• Korean Journal of Heritage: History & Science
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• v.46 no.4
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• pp.64-77
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• 2013

In China, archaeological research on Xiongnu started later than in foreign countries. In the late $19^{th}$ century, several Russian archaeologists started to study Xiongnu's archaeological culture. However, since the late $20^{th}$ century, archaeological research of the Xiongnu in China quickly gained speed. The Xiongnu culture has been reported in Mongolia, northern steppe of China and eastern part of Eurasian steppe. Mainly, Xiongnu sites, dated from the late 2nd century B.C. to the 1st century A.D., are reported on the west side of Baikal Lake(Zabaikal), Mongolia and the Inner Mongolia of China. Based on the historical records and the archaeological remains, the North Xiongnu culture is defined to be the remains of Zabaikal, and the South Xiongnu culture the archaeological remains of Northern China. The expelled North Xiongnu, while fleeing to the western part of Eurasia, left traces of their own archaeological remains in southern Kazakhstan, Xinjiang of China, Altai, and finally appeared in the Europe as Huns. In order to adapt to the environment of northern steppe of China, Xiongnu used a nomadic economic system, giving uniqueness to its iron works. The most characteristic iron works of the Xiongnu is the highly-sophisticated iron weapons. Compared with the iron works of agricultural economic society, Xiongnu iron-works are short of production tools and various vessels. The "Nomadic type" iron works found in Xiongnu area date back to the Warring Country period or slightly later. Further research need to be conducted on "Nomadic type" Xiongnu iron works.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.229-235
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• 2019

As the demand for broadband multimedia including the Internet explosively increases, the advancement of the subscriber network is becoming the biggest issue in the telecommunication industry due to the surge of data traffic caused by the emergence of new services such as smart phone, IPTV, VoIP, VOD and cloud services. In this paper, we have developed WDM(Wavelength Division Multiplexing)-PON(passive optical network) based on the 1-Gigabit Reach Externder (RE) technique to reduce optical core. Particularly, in order to strengthen the market competitiveness, we considered low cost, miniaturization, integration technique, and low power of optical parts. In addition, we have developed a batch system by integrating all techniques for reliability, remote management through the development of transmission distance extension and development of capacity increase of optical line by using RE technology in existing PON network. Based on system interworking with existing commercial 1G PON devices, it can be worthy of achievement of wide nationalization and optical core reduction by using this developed system. Based on these results, we are studying development of 10G PON technology.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.184-192
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• 2019

Compared to 31-mode rings, 33-mode rings are highly utilized as wide bandwidth underwater acoustic transducers because the electro-mechanical coupling and piezoelectric constant d are high. On the other hand, the 31-mode ring is an axial symmetry structure, so it is possible to model it as a simple two-dimensional asymmetrical model for numerical analysis, but the 33-mode ring requires a three-dimensional numerical analysis. That is, a lot of computing resources and computation time are required. In this study, the effective material properties of an equivalent 31-mode ring were derived to simulate the electro-mechano-acoustical responses of the 33-mode ring transducer. Using the effective material properties derived from this study, a numerical analysis of rings in vacuum, air backed rings in water, and FFR (Free Flooded Ring) transducers were performed to compare the responses of 33-mode rings.

• Journal of Mushroom
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• v.17 no.2
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• pp.70-77
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• 2019

This study was carried out to analyze the physiological activities of wild mushroom extracts collected from the Gangwon-do, Gyeonggi-do, and Chungcheongbuk-do provinces in Korea. Among the wild mushroom extracts, those of Clitocybe robusta and Leucopaxillus giganteus (OK829) showed the highest DPPH radical scavenging activities. Nitrite scavenging activity of the L. giganteus extract (OK811) was determined to be 64.1%, which is considerably higher than those of the other mushroom extracts analyzed in this study. The total polyphenol levels in Suillus granulatus, L. giganteus (OK829), and Amanita manginiana extracts were found to be 19.7 mg GAE/g, 20.2 mg GAE/g, and 22.3 mg GAE/g, respectively. To determine their anti-inflammatory effects, nitric oxide production, and cell viability, NO measurement and MTT assays were performed using lipopolysaccharide (LPS)-treated RAW 264.7 cells. The levels of nitric oxide (NO) produced by the C. robusta and Hypholoma fasciculare extracts were remarkably lower than those produced by the others. In our MTT assay, the extracts of S. granulatus, L. giganteus (OK811), and Lactarius chrysorrheus showed high cell viabilities of 40.3%, 48.3%, and 43.2%, respectively. These results can provide the fundamental data for extracting useful compounds from wild mushrooms.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.132-141
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• 2019

The necessity of transmitting video data over a narrow-bandwidth exists steadily despite that video service over broadband is common. In this paper, we propose a scalable video coding framework for low-resolution video transmission over a very narrow-bandwidth network by super-resolution of decoded frames of a base layer using a convolutional neural network based super resolution technique to improve the coding efficiency by using it as a prediction for the enhancement layer. In contrast to the conventional scalable high efficiency video coding (SHVC) standard, in which upscaling is performed with a fixed filter, we propose a scalable video coding framework that replaces the existing fixed up-scaling filter by using the trained convolutional neural network for super-resolution. For this, we proposed a neural network structure with skip connection and residual learning technique and trained it according to the application scenario of the video coding framework. For the application scenario where a video whose resolution is $352{\times}288$ and frame rate is 8fps is encoded at 110kbps, the quality of the proposed scalable video coding framework is higher than that of the SHVC framework.

• The Journal of the Acoustical Society of Korea
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• v.38 no.1
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• pp.56-65
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• 2019

The Indo-Pacific bottlenose dolphins (Tursiops aduncus) are a toothed whale using echolocation clicks and have been studied continuously abroad. However, most studies on this whale's clicks were performed about captive animals and, in Korea, only the studies of the whistle sounds of this animal were done. In this paper, acoustic characteristics of clicks were analyzed about the free-ranging Indo-Pacific bottlenose dolphins living in the coast of the Jeju Island. Acoustic parameters such as signal duration, 1st and 2nd peak frequency, 3 dB and 10 dB bandwidth for acoustic characteristics were calculated and compared with those of Australian species. As a result, the signal durations had average of $38{\mu}s$ and most clicks were within range of $20{\mu}s-60{\mu}s$. The two types of bandwidths showed both narrowband and broadband characteristics, and bimodal signal characteristics were confirmed through the 1st peak frequencies(average of $96kHz{\pm}18kHz$) and the 2nd peak frequencies(average of $69kHz{\pm}19kHz$).

• Journal of Mushroom
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• v.19 no.1
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• pp.41-50
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• 2021

The aim of the study was to obtain the extracts of various native wild mushrooms and select the useful resources though biological activity evaluation. The anti-oxidant potential, nitrite scavenging activity, and ��-glucan content of wild mushrooms collected from Eumseong and Bonghwa in Korea were investigated. Based on the results of this study, Ganoderma lingzhi (OK1362) showed the highest DPPH radical scavenging activity (73.2%), ferric reducing anti-oxidant power (0.134), reducing power (0.155), nitrite scavenging activity (53.6%), total polyphenol content (28.9 mg GAE/g), flavonoid content (10.0 mg QE/g), and ��-glucan content (25.2%) when compared to other wild mushrooms sampled in this study. In addition, it was confirmed that Perenniporia fraxinea (OK1360), Amanita sp. (OK1398), and Russula sp. (OK1406) had relatively high anti-oxidant and nitrite scavenging potentials. In conclusion, our results can provide fundamental data for extracting beneficial compounds from wild mushrooms.

• The Journal of Korean Philosophical History
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• no.39
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• pp.195-220
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• 2013

The 'Localization' & the 'Popularization' issues always play an important role at the Chinese Marxism. The Chinese Communist Party (C.C.P) is still emphasizing the 'Localization', but the 'Popularization' did not received the Chinese theorists' attention. Therefore a new theory in 'Popularization of Chinese Marxism' is very small. But at the 17th National Convention, C.C.P offered a suggestion that entitled "Lead the popularization of Marxism in China". And diversity theorization involved popularization of Marxism is in motion by Chinese theoretician. Throughout history of Chinese Marxism, the first theoretician who raised an objection of the popularization of Marxism in China is Aisiqi, and his achievements in this field are unequaled. His Popular philosophy is the most typical book on the popularization of Marxism in China. In the 1930s, China faced a serious crisis, Chinese intelligentsia & mass desperately wanted an idea to unify the country. Many intellectuals have latched on to the Marxism, especially Aisiqi was absorbed in the important assignment that how can bring out leadership of Marxism, how can popularize abstract and profound principle of Marx philosophy. Aisiqi's Popular Philosophyis marked by the 'Localization' & the 'Popularization', after this book is published, had a big impact on Chinese Revolution. The purpose of this thesis is a meaning through the Popular Philosophy consideration and evaluation to get to the bottom of that the C.C.P offered a suggestion with 'Popularization of Chinese Marxism'.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.278-286
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• 2022

In this study, a 33-mode Free-Flooded Ring (FFR) transducer was designed to apply piezoelectric single crystal PIN-PMN-PT, which has high piezoelectric constants and electromechanical coupling coefficient. To ensure low-frequency high transmitting sensitivity characteristics with a small size of FFR transducer, the commercial FFR transducer based on piezoelectric ceramics was compared. To develop the FFR transducer with broadband characteristics, a piezoelectric segmented ring structure inserted with inactive elements was applied. The oil-filled structure was applied to minimize the change of acoustic characteristics of the ring transducer. It was verified that the transmitting voltage response, underwater impedance, and beam pattern matched the finite element numerical simulation results well through an acoustic test. The difference in the transmitting voltage response between the measured and the simulated results is about 1.3 dB in cavity mode and about 0.3 dB in radial mode. The fabricated FFR transducer had a higher transmitting voltage response compared to the commercial transducer, but the diameter was reduced by about 17 %. From this study, it was confirmed that the feasibility of a single crystal-applied FFR transducer with compact size and high-power characteristics. The effectiveness of the performance prediction by simulation was also confirmed.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.570-575
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• 2022

The MX-S2X, utilizing high-frequency broadband communication technology, provides a reliable connection between land, ship, and facilities. This technology is expected to be effectively utilized as a future maritime communication infrastructure in the upcoming mixed navigational situation among autonomous and manned and/or unmanned ships. Following the physical layer design and M&S-based performance analysis of the MX-S2X system to overcome maritime multipath fading, this paper confirms the optimized and detailed design of physical layer hardware and implemented it to verify the performance. The PER(Packet Error Rate) performance was then measured by configuring a test environment to verify the implemented hardware. The results showed that the performance degradation was 0.2 dB in the AWGN environment and 1.2 dB in the Multi-path Fading on Sea Environment, thus confirming the successful implementation of the physical layer.