• Korean Journal of Materials Research
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• v.27 no.4
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• pp.221-228
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• 2017

Various morphologies of copper oxide (CuO) have been considered to be of both fundamental and practical importance in the field of electronic materials. In this study, using Cu ($0.1{\mu}m$ and $7{\mu}m$) particles, flake-type CuO particles were grown via a wet oxidation method for 5min and 60min at $75^{\circ}C$. Using the prepared CuO, AlN, and silicone base as reagents, thermal interface material (TIM) compounds were synthesized using a high speed paste mixer. The properties of the thermal compounds prepared using the CuO particles were observed by thermal conductivity and breakdown voltage measurement. Most importantly, the volume of thermal compounds created using CuO particles grown from $0.1{\mu}m$ Cu particles increased by 192.5 % and 125 % depending on the growth time. The composition of CuO was confirmed by X-ray diffraction (XRD) analysis; cross sections of the grown CuO particles were observed using focused ion beam (FIB), field emission scanning electron microscopy (FE-SEM), and energy dispersive analysis by X-ray (EDAX). In addition, the thermal compound dispersion of the Cu and Al elements were observed by X-ray elemental mapping.

• Journal of Information Technology Applications and Management
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• v.25 no.4
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• pp.185-196
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• 2018

This study investigates the social network among authors to improve the quality of Panel researches. Korea Health Panel (KHP), implemented by the collaborative work between KIHASA (Korea Institute for Health and Social Affairs) and NHIC (National Health Insurance Service) since 2008, provides a critical infrastructure for policy making and management for insurance system and healthcare service. Using bibliographic data extracted from academic databases, eighty articles were extracted in domestic and international journals from 2008 to 2014, April. Data were analyzed by NetMiner 4.0, social network analysis software, to identify the extent to which authors are involved in healthcare use research and the patterns of collaboration between them. Analysis reveals that most authors publish a very small number of articles and collaborate within tightly knit circles. Centrality measures confirm these findings by revealing that only a small percentage of the authors are structurally dominant, and influence the flow of communication among others. It leads to the discovery of dependencies between the elements of the co-author network such as affiliates in health panel communities. Based on these findings, we recommend that Korea Health Panel could benefit from cultivating a wider base of influential authors and promoting broader collaborations.

• Korean Journal of Organic Agriculture
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• v.29 no.3
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• pp.397-414
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• 2021

As the agricultural population continues to age, the shortage of labor is worsening. To respond to this, Machinery Operators, those who work on behalf of farmers, are on demand. This study examines the cases in Imsil, Sunchang, and Namwon in Jeollabuk-do, where such agencies are in action, and analyzes the elements of their success and customer satisfaction. A survey was circulated among the farmers who used these agricultural agencies, and a total of 180 responses were submitted. A multiple regression analysis was conducted to prove our thesis. The study shows that the agricultural assistance provided by the Machinery Operators did help in ameliorating the shortage of labor, and resulted in high customer satisfaction. In particular, it was analyzed that Assurance and responsiveness had a significant positive effect on satisfaction. In addition, satisfaction was analyzed to fully mediate between service quality and intention to reuse. This study provides further support for the need to expand the institution of Machinery Operators and to encourage agricultural agencies in order to address the shortage of labor in rural areas due to aging.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.997-1002
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• 2022

Oxyapatite[Ca₂Nd₈(SiO₄)₆O₂] glass-ceramics have been suggested as wasteforms for the immobilisation of rare-earth radioactive nuclides because of their high waste-loading capability and good chemical durability. In particular, a partitioning effect is predicted to contribute to an enhancement of corrosion resistance in glass-ceramics compared with that of conjugate glasses of the same composition. Because rare-earths are inherently insoluble nuclides, detection of changes in corrosion behavior between glass-ceramics and conjugate glasses under normal conditions is not easy. In this study, therefore, we revealed the partitioning effect by exposing glass-ceramics and glasses to solution of pH 2, 7 and 10 at 90 ℃ for 20 d. In addition, we proposed the corrosion mechanism for oxyapatite glass-ceramics under various corrosion conditions. Especially, the glassy phase dissolved first, followed by the oxyapatite phase during pH 7 corrosion.

• The Korean Journal of Physiology and Pharmacology
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• v.28 no.2
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• pp.165-181
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• 2024

The slow and regular pacemaking activity of midbrain dopamine (DA) neurons requires proper spatial organization of the excitable elements between the soma and dendritic compartments, but the somatodendritic organization is not clear. Here, we show that the dynamic interaction between the soma and multiple proximal dendritic compartments (PDCs) generates the slow pacemaking activity in DA neurons. In multipolar DA neurons, spontaneous action potentials (sAPs) consistently originate from the axon-bearing dendrite. However, when the axon initial segment was disabled, sAPs emerge randomly from various primary PDCs, indicating that multiple PDCs drive pacemaking. Ca²⁺ measurements and local stimulation/perturbation experiments suggest that the soma serves as a stably-oscillating inertial compartment, while multiple PDCs exhibit stochastic fluctuations and high excitability. Despite the stochastic and excitable nature of PDCs, their activities are balanced by the large centrally-connected inertial soma, resulting in the slow synchronized pacemaking rhythm. Furthermore, our electrophysiological experiments indicate that the soma and PDCs, with distinct characteristics, play different roles in glutamate-induced burst-pause firing patterns. Excitable PDCs mediate excitatory burst responses to glutamate, while the large inertial soma determines inhibitory pause responses to glutamate. Therefore, we could conclude that this somatodendritic organization serves as a common foundation for both pacemaker activity and evoked firing patterns in midbrain DA neurons.

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.245-262
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• 2013

We analyzed 29 surface sediment samples in five submarine volcanoes (TA12, TA19, TA22, TA25, and TA26) located in the southern part of the Tonga arc for trace elements and rare earth elements to investigate characteristics of the hydrothermal alteration of surface sediments. Based on analytical results of trace element and rare earth element (REE), surface sediments of TA12, TA19, and TA22 submarine volcanoes, which are located in the northern part of the study area, were very little or not influenced by hydrothermal fluids. In contrast, some stations of TA25 and TA26 submarine volcanoes were strongly affected by hydrothermal fluids. However, these two submarine volcanoes showed different features in element concentration in the sediments. Some stations of TA25 submarine volcano showed enrichment of Ni, Cu, Sn, Zn, Pb, Cr, Cd, Sb, W, Ba, Ta, Rb, Sr, and As, however, those of TA26 submarine volcano showed enrichment of Sn, Zn, Pb, Cd, Sb, Ba, Rb, and Sr. Stations which enriched trace elements were observed, enriched REEs were also observed. Average upper continental crust (UCC)-normalized REE patterns of the surface sediments generally showed low light REE (LREE) abundances and increased heavy REE (HREE) abundances. Eu enrichment was identified at several stations of TA25 and TA26 submarine volcanoes. In addition, enrichment of Ce was found at some stations of TA26 submarine volcano and these enrichment patterns were similar with hydrothermal fluid of near stations. Furthermore, TA25 and TA26 submarine volcanoes showed different enrichment characteristics of trace elements and REE. Trace elements were concentrated at TA25 submarine volcano. TA26 submarine volcano, on the other hand, observed highly enrichment of REE especially, Eu and Ce. As a result of the investigation, the characteristics and concentrations of REEs and trace elements in the surface sediments of each submarine volcano can be applied to identify hydrothermal alteration of sediments during exploration for hydrothermal deposits.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.69-79
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• 2009

Major and trace elements were analyzed in three core sediments to investigate geochemical characteristics of East Sea sediments and provenance changes during late Quaternary in Ulleung Basin. Comparing with Yellow and South Sea sediments, contents of major elements were generally similar while contents of trace elements were significantly different. Furthermore, within this basin, there were some variabilities in trace element compositions. In the western slope sediments (WS), Mo was enriched over 6 times as much as other sites. On the other hand, Zr, Nb, Hf and Ta were enriched in basin sediments (Basin), and Ca and Cs were enriched in southern slope sediments (SS). After excluding elements derived from biogenic, authigenic and diagenetic origins, the lithogenic elements (K, Ti, Cs, Zr, Nb, Hf and Ta) could be classified into three groups from the comparison of element/Al ratios among cores. The first group consisted of elements (K and Ti) that showed the nearly similar element/Al ratios among three cores. The second group contained Cs which showed significant difference between two slope sediments. The third group elements (Zr, Nb, Hf and Ta) showed highly enriched in basin relative to both slope areas. The depth profiles of metal/Al ratios in basin sediments provided the following interpretation for the compositions of sediment and their variation. From 10,000 yr B.P. to 7,000 yr B.P. two lithogenic components (volcanic ashes and western slope sediments) were mixed and deposited in the basin. After 7,000 yr B.P., however, southern slope sediments were mixed with volcanic ashes and deposited in basin area. This event of source change is nearly close to inflow period of the Tsushima Warm Current to Ulleung Basin. Thus, it might be suggested that element geochemistry in Ulleung basin sediment indicate the change of current system in the study area.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.71-76
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• 2008

H.264(or MPEG-4/AVC pt.10) is a high performance video coding standard, and is widely used. Variable length code (VLC) of the H.264 standard compresses data using the statistical distribution of values. A decoder parses the compressed bit stream and searches decoded values in lookup tables, and the decoding process is not easy to implement by hardware. We propose an architecture of variable length decoder(VLD) for the H.264 baseline profile(BP) L4. The CAVLD decodes syntax elements using the combination of arithmetic units and lookup tables for the optimized hardware architecture. A barral shifter and a first 1's detector parse NAL bit stream, and are shared by Exp-Golomb decoder and CAVLD. A FIFO memory between CAVLD and the reorder unit and a buffer at the output of the reorder unit eliminate the bottleneck of data stream. The proposed VLD is designed using Verilog-HDL and is implemented using an FPGA. The synthesis result using a 0.18um standard CMOS technology shows that the gate count is 22,604 and the decoder can process HD($1920{\times}1080$) video at 120MHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.80-88
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• 2008

In this paper, the block cipher algorithms, 3-DES(Triple Data Encryption Standard), AES(Advanced Encryption Standard), SEED, HASH(SHA-1), which are domestic and international standards, have been implemented as an integrated cryptographic engine for smart card applications. For small area and low power design which are essential requirements for portable devices, arithmetic resources are shared for iteration steps in each algorithm, and a two-level clock gating technique was used to reduce the dynamic power consumption. The integrated cryptographic engine was verified with ALTERA Excalbur EPXA10F1020C device, requiring 7,729 LEs(Logic Elements) and 512 Bytes ROM, and its maximum clock speed was 24.83 MHz. When designed by using Samsung 0.18 um STD130 standard cell library, the engine consisted of 44,452 gates and had up to 50 MHz operation clock speed. It was estimated to consume 2.96 mW, 3.03 mW, 2.63 mW, 7.06 mW power at 3-DES, AES, SEED, SHA-1 modes respectively when operating at 25 MHz clock. We found that it has better area-power optimized structure than other existing designs for smart cards and various embedded security systems.

• Sijohaknonchong
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• v.30
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• pp.91-107
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• 2009

This study is to examine how Sijo is being accommodated to modern Gagok by comparing them. In details, the work is about comparison between three verses in Sijo and twofold grouping in modern Gogok, JoongYuUm in traditional Gagok, YuBak in Sijo, the interlude, ADanSungJang, and changing verses in modern Gagok. First point is about three verses in Sijo and a rhythm of twofold grouping in modern Gagok. In particular, modern Gagok is treated as a group of twofold leaving three verses of Sijo. The way is chosen that whether it sets on an interlude into a song or the third part of three verses in Sijo is extended to avoid its logic of music and poem. Second, the discussion moves points on between an interlude in traditional Gagok and in Sijo. In the process of grouping twofold in modern Gagok, the parts which are interludes of both in traditional Gagok and in Sijo, combined with the interlude of the modern Gagok. It shows that the modern Gagok is affected on both the traditional Gagok and the Sijo. In addition, it explains elements of ADanSungJang - - tones and sounds in the modern Gagok. Originally, the traditional Gagok and sijo are composed of tones and sounds. At this point, tones are short, whereas sounds should be longer. This kind of way in the song has appeared on the modern Gagok of Hong, Nan-Pa. Lastly, the factors is about changing verses of modern Gagok. The one of differences between the modern Sijo and traditional Sijo is verses. For example, when it comes to sijo by Lee, Eun-Sang, he used to create his sijo with three verses. Hence, he did not change verses on his works. Whereas, the modern song "The Spring Lady" by Hong, Nan-Pa has shown the phenomenon that is separating three verses into six verses. It is noticeable that this phenomenon in "The Spring Lady" has the same bases with the modern Sijo.