• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1639-1645
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• 2015

In UHD high-speed video transmission system, when a signal within certain frequency region coincides electrically and structurally, the system becomes unstable because the energy is concentrated, and signal flux is interfered and distorted. For the instability, power integrity analysis should be conducted. To remove the signal distortion for MLB, using a high-frequency design technique for EMI phenomenon, EMI which radiates electromagnetic energy fluxed into power layer was analyzed considering system stabilization. In this paper, we proposed an adaptive MLB design method which minimizes high-frequency noise in MLB structure, enhances signal integrity and power integrity, and suppresses EMI. The characteristic impedance for multi-layer circuit board proposed in this study were High-Speed Video Differential Signaling(HSVDS) line width w = 0.203, line gap d = 0.203, beta layer height h = 0.145, line thickness t = 0.0175, dielectric constant ε_r = 4.3, and characteristic impedance Zdiff = 100.186Ω. When high-speed video differential signal interface board was tested with optimized parameters, the magnitude of Eye diagram output was 672mV, jittering was 6.593ps, transmission frequency was 1.322GHz, signal to noise was 29.62dB showing transmission quality improvement of 10dB compared to previous system.

• Korea Real Estate Review
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• v.27 no.3
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• pp.87-102
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• 2017

The purpose of this study was to compare the taxation equity of non-residential collective real estate based on its standard market prices set by National Tax Service and those for taxation set by the Ministry of Government Administration and Home Affairs with that of the apartment houses in Seoul, South Korea. The study findings were as follows. First, the analysis results of the standard market price rates of non-residential collective real estate pointed to a huge gap in the assessment rate (AR) of the taxation standards among the Gu offices. Second, there was a big coefficient of dispersion (COD) in the standard market prices of non-residential collective real estate, which confirmed the presence of horizontal inequity. Finally, there was regressive vertical inequity, which leads to the undervaluation of high-value assets, in the standard market prices of non-residential collective real estate. The evaluation of the standard market prices of non-residential collective real state should thus reflect the market prices and the addition and assessment of the land and buildings to achieve taxation equity. Based on these findings, it is hoped that this study will make a significant contribution to the improvement of the official announcement system for non-residential real estate based on real transactions during the shift to such system.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3367-3378
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• 2021

The design phase and safety assessment of Generation IV liquid metal-cooled fast reactors calls for the improvement of fuel pin performance codes, in particular the enhancement of their predictive capabilities towards uranium-plutonium mixed oxide fuels and stainless-steel cladding under irradiation in fast reactor environments. To this end, the current capabilities of fuel performance codes must be critically assessed against experimental data from available irradiation experiments. This work is devoted to the assessment of three European fuel performance codes, namely GERMINAL, MACROS and TRANSURANUS, against the irradiation of two fuel pins selected from the SUPERFACT-1 experimental campaign. The pins are characterized by a low enrichment (~ 2 wt.%) of minor actinides (neptunium and americium) in the fuel, and by plutonium content and cladding material in line with design choices envisaged for liquid metal-cooled Generation IV reactor fuels. The predictions of the codes are compared to several experimental measurements, allowing the identification of the current code capabilities in predicting fuel restructuring, cladding deformation, redistribution of actinides and volatile fission products. The integral assessment against experimental data is complemented by a code-to-code benchmark focused on the evolution of quantities of engineering interest over time. The benchmark analysis points out the differences in the code predictions of fuel central temperature, fuel-cladding gap width, cladding outer radius, pin internal pressure and fission gas release and suggests potential modelling development paths towards an improved description of the fuel pin behaviour in fast reactor irradiation conditions.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.15-21
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• 2019

We investigated the structural, electrical and optical properties of zinc oxide (ZnO) ultra-thin films grown at $150^{\circ}C$ by atomic layer deposition (ALD). Diethylzinc and deionized water were used as metal precursors and reactants, respectively, for the deposition of ZnO thin films. The growth rate per ALD cycle was a constant 0.21 nm/cycle at $150^{\circ}C$, and samples below 50 cycles had amorphous properties due to the relatively thin thickness at the initial ALD growth stage. With the increase of the thickness from 100 cycles to 200 cycles, the crystallinity of ZnO thin films was increased and hexagonal wurtzite structure was observed. In addition, the particle size of the ZnO thin film increased with increasing number of ALD cycles. Electrical properties analysis showed that the resistivity value decreased with the increase of the thin film thickness, which is correlated with the decrease of the grain boundary concentration in the thicker ZnO thin film due to the increase of grain size and the improvement of the crystallinity. Optical characterization results showed that the band edge absorption in the near ultraviolet region (300 nm~400 nm) was increased and shifted. This phenomenon is due to the increase of the carrier concentration with the increase of the ZnO thin film thickness. This result agrees well with the decrease of the resistivity with the increase of the thin film thickness. Consequently, as the thickness of the thin film increases, the stress on the film surface is relaxed, the band gap decreases, and the crystallinity and conductivity are improved.

• The Journal of Society for e-Business Studies
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• v.24 no.1
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• pp.29-48
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• 2019

Recently, product design innovation to improve user experience has been perceived as a core element of enterprise competitiveness due to the fierce market competition and decrease of the technological gap between companies, but there is insufficient services to support the product experience evaluation of small and medium-sized companies (SMCs). The aim of this study is to develop a web-based product user experience evaluation and certification system supporting product design practices for SMCs. For system interface design, we conducted systematic functional requirement elicitation methods such as user survey, workflow analysis, user task definition, and function definition. Then main functions, information structure, navigation method, and detailed graphic user interfaces were developed with consideration of user interactions and requirements. In particular, it provides the databases for evaluation efficiency to support the evaluation process above a certain level of performance and efficiency, and knowledge databases to utilize in the evaluation and product design improvement. With help of the developed service platform, It is expected that the service platform would enhance SMCs' product development capability with regard to the user experience evaluation by connecting the consulting firms with SMCs.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.1
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• pp.51-66
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• 2022

SST (Sea Surface Temperature) is based on the atmosphere-ocean interaction, one of the most important mechanisms for the Earth system. Because it is a crucial oceanic and meteorological factor for understanding climate change, gap-free grid data at a specific spatial and temporal resolution is beneficial in SST studies. This paper examined the production of daily SST grid maps from 137 stations in 2020 through the ordinary kriging with variogram optimization and their accuracy assessment. The variogram optimization was achieved by WLS (Weighted Least Squares) method, and the blind tests for the interpolation accuracy assessment were conducted by an objective and spatially unbiased sampling scheme. The four-round blind tests showed a pretty high accuracy: a root mean square error between 0.995 and 1.035℃ and a correlation coefficient between 0.981 and 0.982. In terms of season, the accuracy in summer was a bit lower, presumably because of the abrupt change in SST affected by the typhoon. The accuracy was better in the far seas than in the near seas. West Sea showed better accuracy than East or South Sea. It is because the semi-enclosed sea in the near seas can have different physical characteristics. The seasonal and regional factors should be considered for accuracy improvement in future work, and the improved SST can be a member of the SST ensemble around South Korea.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.41-50
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• 2014

The purpose of this study is to evaluate the High Rate Spiral Clarifier(HRSC) availability for the improvement of polluted retention pond water quality. A lab scale and a pilot scale test was performed for this. The fluid flow patterns in a HRSC were studied using Fluent which is one of the computational fluid dynamic(CFD) programs, with inlet velocity and inlet diameter, length of body($L_B$) and length of lower cone(Lc), angle and gap between the inverted sloping cone, the lower exit hole installed or not installed. A pilot scale experimental apparatus was made on the basis of the results from the fluid flow analysis and lab scale test, then a field test was executed for the retention pond. In the study of inside fluid flow for the experimental apparatus, we found out that the inlet velocity had a greater effect on forming spiral flow than inlet flow rate and inlet diameter. There was no observable effect on forming spiral flow LB in the range of 1.2 to $1.6D_B$(body diameter) and Lc in the range of 0.35 to $0.5L_B$, but decreased the spiral flow with a high ratio of $L_B/D_B$ 2.0, $Lc/L_B$ 0.75. As increased the angle of the inverted sloping cone, velocity gradually dropped and evenly distributed in the inverted sloping cone. The better condition was a 10cm distance of the inverted sloping cone compared to 20cm to prevent turbulent flow. The condition that excludes the lower exit hole was better to prevent channeling and to distribute effluent flow rate evenly. From the pilot scale field test it was confirmed that particulate matters were effectively removed, therefore, this apparatus could be used for one of the plans to improve water quality for a large water body such as retention ponds.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.52-63
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• 2014

This is the study on users' perception gap about the effects of leisure space development of the Han River Citizen Park according to leisure constraints and was to identify leisure constraints expressed when using Han River Citizen Park and identify perception on positive and negative impacts according to use behavior characteristics of Han River Citizen Park and leisure space development. In order to compare and analyze the perception gap about the leisure space development of Han River Citizen Park users according to leisure constraints, we classified information and resources, economic affordability, free time on leisure activities in Han River Citizen Park into high influence group and low influence group and did an in-depth analysis. The results are as follows. First, Han River Citizen Park has the nature of neighborhood use with little influence on leisure constraints such as jogging and marathon, biking etc. including walking and relaxation and was a place to visit for simple exercises. Second, in the effects according to leisure space development of Han River Citizen Park, affordable leisure activity costs and ease of access were evaluated the most highly and congestion due to increasing users, increase in administrative operating budget and management personnel were concerned the most. Third, the leisure constraints in Han River Citizen Park were affected in the order of free time, economic affordability, information and resources. There were also perception gaps in congestion due to an increase in administrative operating budget and management personnel, increase in users including improvement of various leisure opportunities and leisure levels, encouragement of pride and attachment for Han river, affordable leisure activity costs depending on the degree of the influence of leisure constraints. Therefore, this study can be said to have the meaning in that we could identify leisure constraints affecting Han River Citizen Park users and resulting perception in leisure space development and revealed that the degree of the influence of leisure constraints varies in the use behavior of leisure space development of Han River Citizen Park and perception of positive and negative development impact. In addition, in order to resolve leisure complaints according to leisure constraints, we studied the need of accompaniment of leisure space operation and management system, development of various customized programs, introduction of recreational space and facilities prioritizing public interest rather than private interest with public relations and information delivery about leisure space of Han River Citizen Park.

• Genomics & Informatics
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• v.21 no.3
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• pp.39.1-39.15
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• 2023

DNA barcoding without assessing reliability and validity causes taxonomic errors of species identification, which is responsible for disruptions of their conservation and aquaculture industry. Although DNA barcoding facilitates molecular identification and phylogenetic analysis of species, its availability in clariid catfish lineage remains uncertain. In this study, DNA barcoding was developed and validated for clariid catfish. 2,970 barcode sequences from mitochondrial cytochrome c oxidase I (COI) and cytochrome b (Cytb) genes and D-loop sequences were analyzed for 37 clariid catfish species. The highest intraspecific nearest neighbor distances were 85.47%, 98.03%, and 89.10% for COI, Cytb, and D-loop sequences, respectively. This suggests that the Cytb gene is the most appropriate for identifying clariid catfish and can serve as a standard region for DNA barcoding. A positive barcoding gap between interspecific and intraspecific sequence divergence was observed in the Cytb dataset but not in the COI and D-loop datasets. Intraspecific variation was typically less than 4.4%, whereas interspecific variation was generally more than 66.9%. However, a species complex was detected in walking catfish and significant intraspecific sequence divergence was observed in North African catfish. These findings suggest the need to focus on developing a DNA barcoding system for classifying clariid catfish properly and to validate its efficacy for a wider range of clariid catfish. With an enriched database of multiple sequences from a target species and its genus, species identification can be more accurate and biodiversity assessment of the species can be facilitated.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.9-17
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• 2014

Purpose: The purpose of this study was to compare zirconia implants with titanium implants from the view point of biomechanical stability and histologic response on osseointegration when those were placed with xenograft materials. Materials and methods: Specimens were divided into two groups; the control group was experimented with eighteen titanium implants which had anodized surface and the experimental group was experimented with eighteen sandblasted zirconia (Y-TZP) implants. At the tibias of six pigs, implants were installed into bone defect sites prepared surgically and treated with resorbable membranes and bovine bone. Two pigs were sacrificed after 1, 4 and 12 weeks respectively. Each implant site was sampled and processed for histologic and histomorphometric analysis. The stability of implants was evaluated with a $Periotest^{(R)}$. And the interfaces between bone and the implant were observed with a scanning electron microscope. Results: In stability analysis there was no significant difference between Periotest values of the control group and the experimental group. In histologic analysis with a light microscope after 4 weeks, there was new bone formation with the resorption of bovine bone and the active synthesis of osteoblasts in both groups. In bone-implant contact percentage there was significant difference between both groups (P<.05). In bone area percentage there was no significant difference between both groups. In analysis of both groups with a scanning electron microscope there was a gap between bone and a surface at 4 weeks and it was filled up with bone formed newly at 12 weeks. Conclusion: When accompanied by xenograft using membrane, bone to implant contact percentage of zirconia implants used in this experiment was significantly less than that of the titanium implants by surface treatment of anodic oxidation. So, it is considered that the improvement of zirconia implant is needed through ongoing research on surface treatment methods for its practical use.