• Economic Analysis
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• v.27 no.1
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• pp.67-90
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• 2021

This study found an interesting fact that the nonlinear relationship structure between volatility and trading volume changed before and after the COVID-19 pandemic according to empirical analysis using Bitcoin (BTC) market data that sensitively reflects investors' trading behavior. That is, their relationship appeared positive (+) in a stable market state before COVID-19 pandemic, as in theory based on the information flow paradigm. In a state under severe market stress due to COVID-19 pandemic, however, their dependence structure changed and even negative (-). This can be seen as a consequence of increased market stress caused by COVID-19 pandemics from a behavioral economics perspective, resulting in structural changes in the asset market and a significant impact on the nonlinear dependence of volatility and trading volume (in particular, their dependence at extreme quantiles). Hence, it should be recognized that in addition to information flows, psychological phenomena such as behavioral biases or herd behavior, which are closely related to market stress, can be a key in changing their dependence structure. For empirical analysis, this study performs a test of Ross (2015) for detecting a structural change, and proposes a Copula Regression Quantiles (CRQ) approach that can identify their nonlinear relationship structure and the asymmetric dependence in their distribution tails without the assumption of i.i.d. random variable. In addition, it was confirmed that when the relationship between their extreme values was analyzed by linear models, incorrect results could be derived due to model specification errors.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.321-335
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• 2023

Monitoring sediment loads in natural rivers is the key process in river engineering, but it is costly and dangerous. In practice, suspended loads are directly measured, and total loads, which is a summation of suspended loads and bed loads, are estimated. This study proposes a real-time sediment discharge monitoring system using the horizontal acoustic Doppler current profiler (H-ADCP) and support vector regression (SVR). The proposed system is comprised of the SVR model for suspended sediment concentration (SVR-SSC) and for total loads (SVR-Q_TL), respectively. SVR-SSC estimates SSC and SVR-Q_TL mimics the modified Einstein procedure. The grid search with K-fold cross validation (Grid-CV) and the recursive feature elimination (RFE) were employed to determine SVR's hyperparameters and input variables. The two SVR models showed reasonable cross-validation scores (R²) with 0.885 (SVR-SSC) and 0.860 (SVR-Q_TL). During the time-series sediment load monitoring period, we successfully detected various sediment transport phenomena in natural streams, such as hysteresis loops and sensitive sediment fluctuations. The newly proposed sediment monitoring system depends only on the gauged features by H-ADCP without additional assumptions in hydraulic variables (e.g., friction slope and suspended sediment size distribution). This method can be applied to any ADCP-installed discharge monitoring station economically and is expected to enhance temporal resolution in sediment monitoring.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.341-350
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• 2023

The templated grain growth (TGG) method has gained significant attention for its ability to produce highly textured piezoelectric ceramics with significantly enhanced performance, making it a promising method for transducer and actuator applications. However, the texturing process using the TGG method requires the optimization of multiple steps, which can be challenging for beginners in this field. Therefore, in this tutorial, we provide an overview of the TGG method mainly based on our previous published works, including its various processing steps such as synthesizing anisotropic-shaped templates with size and size distribution control using the molten salt synthesis technique, tape casting, and identifying key factors for proper alignment of the templates in the target matrix system. Our goal is to provide a resource that can serve as a basic reference for researchers and engineers looking to improve their understanding and utilization of the TGG method for producing textured piezoelectric ceramics.

• The Korean Journal of Franchise Management
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• v.3 no.2
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• pp.39-54
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• 2012

Franchise system in Korea has been developed in different way compared with American way of franchising based on mutual contract and intellectual property context. Korean franchising is mostly based on product distribution franchise concept rather than business format franchise in which franchisor makes revenue sources from providing their products as much as possible thru group purchasing and logistics rather than receiving royalty. Many franchise enterprises from Korea drive to enter into global franchise market based on the successful performance of Korean way of franchising. Korean enterprises are required to prepare completely for research and survey regarding local culture, custom, way of life and legal matters etc. when entering into global franchise market to gain a substantial performance. CaffeBene recently entered into American franchise business with success, and many other Korean franchise enterprises have a deep interest in proceeding with global franchise business modeling CaffeBene case. There is no Korean franchise enterprise in United Kingdom in which service franchise area in particular with personal service is considered to become a promising and potential franchise business and many people show a great interest in Oriental foods and beverages with well-being trend. Korean franchise enterprises have now access to United Kingdom easier because IT industry including internet of the country have been developed by leaps and bounds since London Olympic in 2012. The purpose of this study is to suggest key success factors and basic strategy such as situation analysis, selecting business format, and marketing strategy for successful launching of franchise business in United Kingdom.

• The Journal of Bigdata
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• v.7 no.2
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• pp.1-9
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• 2022

In the global era, the importance of imported food safety management is increasing. Address information of overseas food companies is key information for imported food safety management, and must be verified for prompt response and follow-up management in the event of a food risk. However, because each country's address system is different, one verification system cannot verify the addresses of all countries. Also, the purpose of address verification may be different depending on the field used. In this paper, we deal with the problem of classifying a given overseas food business address into the administrative district level of the country. This is because, in the event of harm to imported food, it is necessary to find the administrative district level from the address of the relevant company, and based on this trace the food distribution route or take measures to ban imports. However, in some countries the administrative district level name is omitted from the address, and the same place name is used repeatedly in several administrative district levels, so it is not easy to accurately classify the administrative district level from the address. In this study we propose a deep learning-based administrative district level classification model suitable for this case, and verify the actual address data of overseas food companies. Specifically, a method of training using a label powerset in a multi-label classification model is used. To verify the proposed method, the accuracy was verified for the addresses of overseas manufacturing companies in Ecuador and Vietnam registered with the Ministry of Food and Drug Safety, and the accuracy was improved by 28.1% and 13%, respectively, compared to the existing classification model.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.519-528
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• 2023

The visual characteristics of the World Cup emblem play an important role in conveying culture and identity, highlighting the key elements of the Games, and strengthening the brand image. This study first investigated the visual elements and theoretical background of the emblem through previous studies. Second, the selection of symbolism, shape, and color was the subject of the study. Third, based on the shape-related theory based on the '100 National Cultural Symbols', the analysis was performed using the 'IRI Color Matching Image Scale' as a tool, and a final conclusion was drawn. The World Cup emblem uses a lot of ethnic and living symbols, and the living and ethnic symbols are expressed in a combination. In the beginning, there were many symmetric shapes, but after that it changed to an asymmetric shape. The curved expression form is more used than the straight expression form. And most of the color arrangement image scale distribution shows light, dynamic and modern color arrangement characteristics. In the future, the World Cup emblem design will continue to use national and living symbols. The shape of the emblem should use curves and asymmetric designs, be intuitive, and directly reflect the theme of the competition. In addition, the national flag color should be used as the main color, and other colors should be used as secondary colors. The combination of colors must match the light, dynamic and modern color characteristics of the IRI color scheme image scale.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.183-190
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• 2006

Minimizing the self weight of long-span deck slabs is one of the key factors for the practical and economic design of a composite two-girder bridge. In this paper, the minimum design thickness and rebar details of prestressed concrete deck slabs for composite two-girder bridges with girder span length from 4 m to 12 m are studied based on the safety and serviceability. The bridge deck slab with minimum thickness is designed as a one-way slab considering orthotropic behavior. Then fatigue safety of the deck slab is examined. Serviceability requirements for the deck slab such as deflection and crack width limits are also examined. The result shows that rebars with diameter less than 16 mm is recommended for the improved fatigue behavior, and, for the deck slab with span length longer than 8 m, the deflection limit governs the minimum design thickness. The result also shows that, for the deck slab with span length longer than 4 m, the distribution rebar requirement in the current Korea Highway Bridge Design Code is not sufficient to maintain the structural continuity in bridge axis as expected from the deck slab with span length shorter than 3 m.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.237-249
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• 2023

This study was carried to establish a new landscape-oriented gardening model based on climate, vegetation, and forest landscape characteristics. In addition, innovative forest garden models were suggested through an integrated approach to the ecological characteristics of forest vegetation communities and existing garden planting types. For the study, the key landscape elements that make up the main forest vegetation community were identified. And the vertical layers and horizontal distribution patterns of the community structure were typified by diagnostic species and their growth forms & habits such as dominant species, character species, and differential species, and degree of dominance-sociability. Based on this, a standardized vegetation structure and formation was developed by stratifying the landscape into main features, minor features, and detailed features according to visual dominant elements. Also, the applicability of the forest garden model was examined by applying the concept of borrowing landscape to representative deciduous broadleaf forests in the temperate northern region of Korea. Additionally, an integrated forest garden models based on the conceptual definition and typology of forest gardens, and a strategic approach to forest vegetation were proposed

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.63-72
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• 2024

Poly (butylene adipate-co-terephthalate) (PBAT) is one of the representative biodegradable polymers with high ductility and processability to replace petroleum-based polymers. Many investigations have been conducted to broaden the applications of PBAT in a variety of industries, including the food packaging, agricultural mulching film, and logistics and distribution fields. Foaming process is widely known technique to generate the cell structure within the polymer matrix, offering the insulation and light weight properties. However, there was no commercially feasible foam product based on biodegradable polymers, especially PBAT, and maintaining a proper melt viscosity of the polymer would be a key parameter for the foaming process. In this study, chemical foaming agent and cross-linking agent were introduced to PBAT, and a compression molding process was applied to prepare a foam sheet. The correlation between cell morphological structures and mechanical and physical properties was evaluated. It was found that PBAT with foam structures effectively reduced the density and thermal conductivity, allowing them to be suitable for applications such as insulation and lightweight packaging or cushion materials.

• Journal of Korean Society of Archives and Records Management
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• v.24 no.2
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• pp.41-63
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• 2024

This study investigated research trends in digital curation indexed in a prominent domestic academic information database. A systematic literature review was conducted on 39 academic papers published from 2009 to 2023. The review examined indexing status according to publication year, venue, academic discipline, research area distribution, research affiliation and occupation, and research types. In addition, network centrality analysis and cohesive group analysis were performed on 69 author keywords. The findings revealed several key points. First, digital curation research peaked in 2015 and 2016 with 5 publications each year, followed by a slight decrease, and then consistently produced 4 or more publications annually since 2019. Second, among the 39 studies, 25 were conducted in interdisciplinary fields, including library and information science, while 11 were in the humanities, such as miscellaneous humanities. The most prominent research areas were theoretical and infrastructural aspects, information management and services, and institutional domains. Third, digital curation research was predominantly led by university-affiliated professors and researchers, with collaborative research more prevalent than solo research. Lastly, analysis of author keywords revealed that "digital curation," "institution," and "content" were the most influential central keywords within the overall network.