• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.537-549
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• 2023

The distribution characteristics of tidal flat sediment components are used as an essential data for coastal environment analysis and environmental impact assessment. Therefore, a reliable classification map of surface sedimentary facies is essential. This study evaluated the applicability of regression kriging to generate a classification map of the sedimentary facies of tidal flats. For this aim, various factors such as the number of field survey data and remote sensing-based auxiliary data, the effect of regression models on regression kriging, and the comparison with other prediction methods (univariate kriging and regression analysis) on surface sedimentary facies classification were investigated. To evaluate the applicability of regression kriging, a case study using unmanned aerial vehicle (UAV) data was conducted on the Hwang-do tidal flat located at Anmyeon-do, Taean-gun, Korea. As a result of the case study, it was most important to secure an appropriate amount of field survey data and to use topographic elevation and channel density as auxiliary data to produce a reliable tidal flat surface sediment facies classification map. In addition, regression kriging, which can consider detailed characteristics of the sediment distributions using ultra-high resolution UAV data, had the best prediction performance compared to other prediction methods. It is expected that this result can be used as a guideline to produce the tidal flat surface sedimentary facies classification map.

• Korea Trade Review
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• v.48 no.2
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• pp.111-127
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• 2023

While the e-commerce market in Southeast Asia is growing, this study aims to derive factors for establishing an entry strategy for the Cambodian e-commerce market where Korean logistics companies can strategically enter in the future. Cambodia is a country where growth and growth potential in the e-commerce market is steadily increasing based on the high youth population ratio, high smartphone penetration rate, the introduction of convenient payment systems, and government-level e-commerce promotion policies. In this study, Korean logistics companies established detailed promotion strategies by deriving factors necessary for Cambodia's entry into the e-commerce market and analyzing their relative importance. The AHP analysis technique derived three top factors for the entry strategy, and each presented four sub-factors. As a result, the importance was shown in the order of 'Market Factor' (0.556), 'Policy and Institutional Factor' (0.295), and 'Corporate Competency Factor' (0.149). As a result of the sub-factors analysis, the importance was found in the order of "Characteristics and Growth Potential of Distribution Channel" (0.230), "Purchasing Power and Awareness Level of Consumers" (0.176), "Cambodia Government's E-commerce Policy and Institutional Support" (0.122), and "Cambodia Government's Logistics Infrastructure Plan" (0.108). In both the upper and lower factors, the characteristics and growth potential of the Cambodian e-commerce market were important, indicating that Korean logistics companies value market size and growth potential to enter the Cambodian e-commerce market. The results of this study can be used as a guideline to help Korean logistics companies make successful inroads into Cambodia, where the e-commerce market is expected to grow in the future.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.90-101
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• 2009

Analysis of multi-channel seismic reflection data from the Southern Ulleung Basin reveals that Plio-Quaternary section in the area consists of nine stacked sedimentary units separated by erosional unconformities. On the southern slope, these sedimentary units are acoustically characterized by chaotic seismic facies without distinct internal reflections, interpreted as debris-flow bodies. Toward the basin floor, the sedimentary units are defined by well-stratified facies with good continuity and strong amplitude, interpreted as turbidite/hemipelagic sediments. The seismic facies distribution suggests that deposition of Plio-Quaternary section in the area was controlled mainly by tectonic movement and sea-level fluctuations. During the Pliocene, sedimentation was mainly controlled by tectonic movements related to the back-arc closure of the East Sea. The back-arc closure that began in the Miocene caused compressional deformation along the southern margin of the Ulleung Basin, resulting in regional uplift which continued until the Pliocene. Large amounts of sediments, eroded from the uplifted crustal blocks, were supplied to the basin, depositing Unit 1 which consists of debris-flow deposits. During the Quaternary, sea-level fluctuations resulted in stacked sedimentary units (2-9) consisting of debris-flow deposits, formed during sea-level fall and lowstands, and thin hemipelagic/turbidite sediments, deposited during sea-level rise and highstands.

• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.193-207
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• 2024

Purpose - With the increase of non-face-to-face activities due to the spread of COVID-19, O2O industry has grown rapidly which reduces contact points between suppliers and consumers. O2O platform is now recognized as an indispensable channel of distribution, but the voice is getting louder that it is necessary to check how it contributes to the performance of suppliers or how its fee system or contract terms affects the expansion of O2O industry as the leading companies tend to monopolize the market. Design/methodology/approach - In this study, the scope was limited to the restaurant industry in which transactions are the most active among the O2O industry and a regression analysis was done on 775 businesses that had used guarantor service from the Seoul Credit Guarantee Foundation. Findings - Analysis on the impact of O2O platform system, information, and service quality on the business performance of the sole proprietors revealed that the system quality represented by ease of use and the information quality determined by level of timely, accurate and reliable information provided to the consumers have a statistically significant effect on the improvement of business performance. In addition, the effect of business performance on the loyalty measured by the likelihood of users continuing to use the service as well as recommending it to others was moderated by the satisfaction with contract terms, not by the fee system. Research implications or Originality - Although the number of O2O platform providers has increased manyfold, the membership rate is no more than 20%, which means that the small business owners are still struggling with digital transformation. In order for the O2O industry, which is now commonplace, to form a healthy ecosystem that satisfies both suppliers and consumers, the standard contract guidelines that are acceptable to both parties must be established and the O2O providers must offer services that help suppliers to improve performance.

• Particle and aerosol research
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• v.19 no.4
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• pp.129-144
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• 2023

The PM_1.0 and PM_2.5 samples were collected synchronously using a single channel particulate sampler equipped with PM_1.0 and PM_2.5 cyclones, respectively, and seasonal mass concentration and chemical composition of PM_1.0 and PM_2.5 were quantified in Seoul and Gwangju in 2021-2022. The mass concentrations of PM_1.0 and PM_2.5 were 17±11 and 22±14 ㎍/m³ in Seoul, and 16±9 and 19±12 ㎍/m³ in Gwangju, respectively. The average ratios of PM_1.0/PM_2.5 were 83±16% in Seoul and 83±7% in Gwangju. The chemical compositions of PM_1.0 and PM_2.5 were similar at both sites with OC component being the most dominant, and NO₃^- increasing from summer to winter, while, the difference of chemical distribution at the two sites was most distinct in the autumn. Gwangju showed a higher proportion of OC and a lower proportion of NO₃^- compared to Seoul during the autumn. Both sites appear to reflect their urban characteristics, with Gwangju also reflecting the impact of biomass combustion as a part of rural activities.

• Journal of Korea Water Resources Association
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• v.57 no.8
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• pp.493-507
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• 2024

RANS-based CFD analysis is widely applied in various engineering fields, including practical hydraulic engineering, due to its high computational efficiency. However, problems of non-physical behavior in the analysis of two phase flow, such as free surfaces, have long been raised. The two-equation turbulence models used in general RANS-based analysis were developed for single phase flow and simulate unrealistically high turbulence energy at the interface where there are abrupt changes in fluid density. To solve this issue, one of the methods recently developed is the buoyancy-modified turbulence model, which has been partially validated in coastal engineering, but has not been applied to open channel flows. In this study, the applicability of the buoyancy-modified turbulence model is evaluated using the VOF method in the open-source program OpenFoam. The results of the uniform flow showed that both the buoyancy-modified k-𝜖 model and the buoyancy-modified k-ω SST model effectively simulated the reduction of turbulence energy near the free surface. Specifically, the buoyancy-modified k-ω SST model accurately simulated the vertical velocity distribution. Additionally, the model is applied to dam-break flows to examine cases with significant surface variation and cavity formation. The simulation results show that the buoyancy-modified turbulence models produce varying results depending on the VOF method and shows non-physical behavior different from experimental results. While the buoyancy-modified turbulence model is applicable in cases with stable surface shapes, it still has limitations in general application when there are rapid changes in the free surface. It is concluded that appropriate adjustments to the turbulence model are necessary for flows with rapid surface changes or cavity formation.

• Journal of Mushroom
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• v.22 no.3
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• pp.122-127
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• 2024

This study was conducted to evaluate the market potential of 'Hwanggeumsantari', a new oyster mushroom variety developed in Gyeonggi Province in 2019, and to derive effective market entry strategies. To objectively assess the marketability of 'Hwanggeumsantari' from various perspectives, a panel of 50 consumers was formed, and surveys and interviews were conducted. Additionally, two Focus Group Interviews were held with distributors in the agri-food sector. The results showed that potential consumers were positive about the color and texture of 'Hwanggeumsantari', but expressed relatively less satisfaction with its shelf life and aroma. Distributors, through tow Focus Group Interviews, evaluated that the product had sufficient market competitiveness, but called for efforts to improve cultivation techniques and enhance price competitiveness. Based on the results of market evaluations by consumers and distributors, a SWOT analysis was conducted. The main strengths identified were its outstanding color and texture, while the main weakness was its freshness issue. Meanwhile, the growing demand for healthy foods and various online sales channels could provide market entry opportunities for 'Hwanggeumsantari', but high sensitivity to price in the case of premium pricing could pose a threat. Consequently, a market entry strategy for 'Hwanggeumsantari' was proposed using a 4P mix approach based on the SWOT analysis results. The product strategy emphasized premium positioning, small packaging, and the development of packaging technology to maintain freshness. The price strategy proposed premium pricing and the operation of incentive programs. The distribution strategy suggested channel diversification, direct stores, or direct sales, while the promotion strategy emphasized storytelling and collaboration with influencers.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.80-87
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• 2010

This study was conducted to develop a reservoir modelling workflow to reproduce the heterogeneous distribution of effective permeability that impacts on the performance of SAGD (Steam Assisted Gravity Drainage), the in-situ bitumen recovery technique in the Athabasca Oil Sands. Lithologic facies distribution is the main cause of the heterogeneity in bitumen reservoirs in the study area. The target formation consists of sand with mudstone facies in a fluvial-to-estuary channel system, where the mudstone interrupts fluid flow and reduces effective permeability. In this study, the lithologic facies is classified into three classes having different characteristics of effective permeability, depending on the shapes of mudstones. The reservoir modelling workflow of this study consists of two main modules; facies modelling and permeability modelling. The facies modelling provides an identification of the three lithologic facies, using a stochastic approach, which mainly control the effective permeability. The permeability modelling populates mudstone volume fraction first, then transforms it into effective permeability. A series of flow simulations applied to mini-models of the lithologic facies obtains the transformation functions of the mudstone volume fraction into the effective permeability. Seismic data contribute to the facies modelling via providing prior probability of facies, which is incorporated in the facies models by geostatistical techniques. In particular, this study employs a probabilistic neural network utilising multiple seismic attributes in facies prediction that improves the prior probability of facies. The result of using the improved prior probability in facies modelling is compared to the conventional method using a single seismic attribute to demonstrate the improvement in the facies discrimination. Using P-wave velocity in combination with density in the multiple seismic attributes is the essence of the improved facies discrimination. This paper also discusses sand matrix porosity that makes P-wave velocity differ between the different facies in the study area, where the sand matrix porosity is uniquely evaluated using log-derived porosity, P-wave velocity and photographically-predicted mudstone volume.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.633-642
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• 2005

We present the sedimentary sequence and distribution pattern of the late Holocene muddy deposits in the northern East China Sea shelf using the high-resolution 'Chirp' profiles. The seismic sedimentary sequence overlying acoustic basement (basal reflector-B) can be divided into two depositional units (Unit 1 and 2) bounded by erosional bounding surface (mid reflector-M). The lower Unit 1 above basal reflector-H is characterized by the acoustically parallel to subparallel reflections and channel-fill facies. The upper Unit 2, up to 7 m in thickness, shows seismically semi-transparent seismic facies and lenticular body form. On the base of sequence stratigraphic concept, these two sediment units have developed during transgression and highstand period, respectively, since the last sea-level lowstand. The transgressive systems tract (Unit 1) lie directly on the sequence boundary (reflector B) that have farmed during the last glacial maximum. The transgressive systems tract in this study consists mostly of complex of delta, fluvial, and tidal deposits within the incised valley estuary system. The maximum flooding surface (reflector M) corresponding to the top surface of transgressive systems tract is obviously characterized by erosional depression. The highstand systems tract (Unit 2) above maximum flooding surface is made up of the mud patch filled with the erosional depression. The high-stand mud deposits showing a circle shape just like a typhoon symbol locates about 140 km off the south of Cheju Island with water depth of $60\~90m$. Coverage area and total sediment volume of the mud deposits are about $3,200km^2$ and $10.7\times10^9\;m^3$, respectively. The origin of the mud patch is interpreted as a result of accumulating suspended sediments derived from the paleo-Yellow and/or Yangtze Rivers. The circular distribution pattern of the mud patch appears to be largely controlled by the presence of cyclonic eddy in the northern East China Sea.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.3
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• pp.143-150
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• 2017

Effects of packaging methods for maintaining the shelf-life and postharvest quality of Korean chive (Allium tuberosum Rotter) usually called buchu in Korea was studied during fall season. Buchu, which has high moisture content and active metabolism after harvest, is characterized by the greater changes in quality during storage and distribution. It is usually packaged in paper box during distribution in domestic channel in Korea where the marketability ends within few days of harvest. In order to maintain the commercial quality of buchu, we tried to use inner film with or without absorbent paper in commercial paper box packaging. The 'Greenbelt' cultivar of buchu was harvested in october and packaged in corrugated paper box (A), in corrugated paper box with micro-perforated high density polyethylene (HDPE) film as inner material (B), a layer of absorbent paper both at the bottom and top of buchu in corrugated paper box (C) and a combination of HDPE film as inner material along with a layer of absorbent paper both at the bottom and top of buchu in corrugated paper box (D), and stored at $5^{\circ}C$ for up to 21 days. Several quality parameters such as fresh weight loss, respiration rate, color, chlorophyll content and sensory qualities were monitored during storage. When buchu was packaged only in paper box, the appearance and quality deteriorated rapidly through decay development thereby sample became unmarketable within 12 days. On the other hand, buchu packaged with inner HDPE film maintained its quality, good visual appearance and exhibited a longer period of marketable life compared to the samples stored in other treatments. However, the use of absorbent paper did not have any significant effect in maintaining quality of buchu. The uses of inner HDPE film was effective in reducing weight loss that resulted better visual appearance of buchu. Results suggest that the use of inner HDPE film in bulk type corrugated paper box packaging and storing at $5^{\circ}C$ could be the optimum condition for commercial storage of buchu. Further investigation on other quality parameters and packaging methods would be useful in maintaining the quality aspects of buchu at postharvest stages.