• 청정기술
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• 제28권2호
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• pp.138-146
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• 2022

Electricity has become a factor that dramatically affects the market economy. The day-ahead system marginal price determines electricity prices, and system marginal price forecasting is critical in maintaining energy management systems. There have been several studies using mathematics and machine learning models to forecast the system marginal price, but few studies have been conducted to develop, compare, and analyze various machine learning and deep learning models based on a data-driven framework. Therefore, in this study, different machine learning algorithms (i.e., autoregressive-based models such as the autoregressive integrated moving average model) and deep learning networks (i.e., recurrent neural network-based models such as the long short-term memory and gated recurrent unit model) are considered and integrated evaluation metrics including a forecasting test and information criteria are proposed to discern the optimal forecasting model. A case study of South Korea using long-term time-series system marginal price data from 2016 to 2021 was applied to the developed framework. The results of the study indicate that the autoregressive integrated moving average model (R-squared score: 0.97) and the gated recurrent unit model (R-squared score: 0.94) are appropriate for system marginal price forecasting. This study is expected to contribute significantly to energy management systems and the suggested framework can be explicitly applied for renewable energy networks.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1433-1439
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• 2009

Best value is the ultimate goal of the owner and can thus have diverse meanings according to the project characteristic, owner's purpose, user groups' payment capability, etc.. Recently, resettlement problems of the marginalized members in the urban regeneration area have been issued in Korea because they have no capability to purchase (or lease) redeveloped housing (or apartment). It means that a minimized production cost for reducing supply price of housing is a key factor in establishing the best value of the marginalized members. The lowest-price bidding system serves the purpose of ensuring a minimized production cost, but due to the low-cost investments, it creates various problems, such as sloppy construction, lowered quality, an increased LCC, and worsening profitability for builders. Thus, to help them resettle, it is necessary to supply affordable housing geared towards a certain appropriate quality and minimum construction costs. Towards this end, this study aimed to propose a cost reduction bidding system based on a technical proposal. The proposed technical-proposal-based cost reduction bidding system consists of the following components: work-unit-based, project-unit-based, and construction-period-reducing technical proposals. These components are evaluated to select the best bidder for a given project. The technical proposal based cost reduction bidding system proposed herein is expected to provide facilities with appropriate supply prices and appropriate quality levels, to bolster the technological competitiveness of builders.

• 유통과학연구
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• 제21권5호
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• pp.31-41
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• 2023

Purpose: Electric vehicle (EV) technology started in 2015 in Thailand. The Thai Government has indicated that 30% of all cars produced in Thailand by 2025 will be EVs. Using EVs in Thailand will reduce road pollution and increase energy efficiency, especially in major cities. Hence, the adoption of EVs in the country has been promoted. This study pointed out that social influence, facilitating conditions, perceived enjoyment, environmental concern, attitude, and perceived behavioral control are key factors affecting the behavioral intention to adopt EVs among logistic and distribution firms in Thailand. Research design, data, and methodology: 500 top management, middle management and purchasing managers of logistic and distribution firms in Thailand are surveyed. The study employed judgmental, convenience, and snowball sampling. Confirmatory Factor Analysis (CFA) and Structural Equation Model (SEM) are the main statistical tools for data analysis. Results: The results show that all determinants impact customers' willingness to adopt EVs, except perceived enjoyment and environmental control. Conclusions: The study proposes to promote the incentives by decreasing electricity prices and endorsing EVs purchase to accelerate the adoption of EVs in Thailand. Therefore, future policies should focus on behavioral intention toward EVs amongst logistic and distribution firms for enhancing the future of mobility in Thailand.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.248-257
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• 2020

This study presents an initial design for a novel system consisting in a coupled nuclear reactor and a phase change material-based thermal energy storage (TES) component, which acts as a buffer and regulator of heat transfer between the primary and secondary loops. The goal of this concept is to enhance the capacity factor of nuclear power plants (NPPs) in the case of high integration of renewable energy sources into the electric grid. Hence, this system could support in elevating the economics of NPPs in current competitive markets, especially with subsidized solar and wind energy sources, and relatively low oil and gas prices. Furthermore, utilizing a prismatic-core advanced high temperature reactor (PAHTR) cooled by a molten salt with a high melting point, have the potential in increasing the system efficiency due to its high operating temperature, and providing the baseline requirements for coupling other process heat applications. The present research studies the neutronics and thermal hydraulics (TH) of the PAHTR as well as TH calculations for the TES which consists of 300 blocks with a total heat storage capacity of 150 MWd. SERPENT Monte Carlo and MCNP5 codes carried out the neutronics analysis of the PAHTR which is sized to have a 5-year refueling cycle and rated power of 300 MW_th. The PAHTR has 10 metric tons of heavy metal with 19.75 wt% enriched UO₂ TRISO fuel, a hot clean excess reactivity and shutdown margin of $33.70 and -$115.68; respectively, negative temperature feedback coefficients, and an axial flux peaking factor of 1.68. Star-CCM + code predicted the correct convective heat transfer coefficient variations for both the reactor and the storage. TH analysis results show that the flow in the primary loop (in the reactor and TES) remains in the developing mixed convection regime while it reaches a fully developed flow in the secondary loop.

• 한국의류학회지
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• 제34권7호
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• pp.1149-1161
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• 2010

This study identifies the dimensions of cosmetics consumption values and the differences in cosmetics brand selection through a cosmetics consumption value group and by product type. The subjects of the study were females over age 20 living in Seoul and Gyeonggi Province between January and February 2008; 427 questionnaires were used for analysis. For data analysis the SPSS 17.0 statistical program was used, and principal component analysis, factor analysis using Varimax rotation, Cronbach's ${\alpha}$ reliability testing, cluster analysis, ANOVA test, and Duncan test were conducted. The results and conclusions of this study are as follows. The dimensions of cosmetics consumption values were found to be the pleasure value, the fashion value, the function value, the brand ostentation value, and the appearance ostentation value. Five types of groups by factor were identified: the group seeking function, the group seeking fashion and brand ostentation, the group seeking pleasure, the group seeking appearance and brand ostentation, and the indifferent group. Second, The group attaching importance to functionality was more likely to select high-priced brands while the group attaching importance to brand awareness were more likely to seek foreign brands, irrespective of product type. As far as base and color cosmetics are concerned, the group attaching importance to pleasure was more likely to select low, medium, and high priced foreign brands, as well as low and medium priced domestic brands. As for body products, the group attaching importance to fashion and brand awareness tended to select low, medium, and high priced domestic brands, as well as high priced foreign brands. By simultaneously purchasing high, medium, and low priced brands, these groups display an ambivalent consumption pattern. This study identified the differing dimensions around cosmetics consumption values and cosmetic brand selection. The research findings helps cosmetic companies set product prices and contributes to cosmetic marketing strategies.

• 한국공간정보시스템학회 논문지
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• 제10권2호
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• pp.25-33
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• 2008

본 연구의 목적은 도시의 질적 성장에 필요한 수공간 확보방안으로 도시화 과정에서 사라진 소하천을 찾아내고 찾아진 소하천을 복원할 때 도시의 현실에 맞는 적절한 경로를 찾는 방법을 찾는 것이다. 연구결과 GIS를 이용하여 도시내의 사라진 소하천을 발견할 수 있었으며 발견된 소하천을 복원할 경우 영향을 주는 요인으로 고도, 토지이용, 지가를 선정하여 각각의 요인별 최적경로를 분석하였고 3가지 요인을 모두 반영한 최적경로를 분석하였다. 3가지 요인이 하천복원에 미치는 영향이 서로 다르기 때문에 중요도에 따른 최적의 가중치를 찾아내고 최적가중치를 이용하여 최적의 복원경로를 추적하는 방법을 개발하였다. 본 연구의 결과는 친환경도시건설과 도시민의 쾌적한 삶을 위해 사라진 하천을 복원경로를 찾는데 기여할 것이다.

• 가족자원경영과 정책
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• 제21권2호
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• pp.95-117
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• 2017

The purpose of this study was to examine the level of anxiety about economic change in middle-aged and elderly people and to analyze the factors that influence this anxiety. The data, derived from Korean General Social Survey(KGSS) were collected from Survey Research Center of Sung Kyun Kwan University. The samples included 821 people over the age of 40, including 529 middle-aged people who were from 40 to 59, and elderly people who were over 60. Multiple regression analysis was used to analyze the research model. The findings from the analysis showed that age and subjective economic status had crucial effects on the entire group's anxiety about unemployment and poverty, housing prices, financial markets, and economic recession in the older life. For the middle-aged group, age in particular had crucial effects on all the components of its anxiety about economic change. For the elderly group, geographical region was the most critical factor that affected its anxiety about economic change, the elderly people who were living in metropolitan area and towns had more anxiety than those who were living in rural areas. In particular, region was the only factor that affected the elderly group's anxiety about financial markets, and economic recession. These results showed that specific age of middle-aged and elderly people had the crucial effects while their sex, educational level, and the employment status of their spouse had no effects on their anxiety about economic change. Objective economic indices such as their earned-income and other income including savings and pensions had no effects on their anxiety level. While as noted above subjective economic indices such as their standard of living compared with their parents, projected economic status, and level of socio-economic success had an effect on anxiety about economic change.

• Asia Pacific Journal of Business Review
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• 제4권2호
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• pp.1-21
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• 2020

The purpose of this research is to investigate young consumer motivation in regards to shopping mall. Young adults are an emerging age group that has economic autonomy and power of making independent decisions. In addition, this young segment providing an interesting challenges and opportunities for marketing professionals. Therefore, it is pertinent to analyse their shopping motivations, so that the marketers can understand and influence the consumption behaviour of this specific group. A survey using self-administered questionnaire was conducted to assess the mall-directed shopping habits and shopping orientations. A total of 164 usable surveys were obtained. In addition of exploratory factor analysis, confirmatory factor analysis and structural equation modeling was applied to prove the hypotheses. We have found that young Australian shoppers were motivated to visit malls primarily by the role enactment and exploration dimensions. They were the strongest motivators which explaining why young Australian consumers patronize malls. Young consumers of Australia enjoyed the mall environment, exploring new things, socializing with friends, comparing prices and the variety of products and services offered. The results of our study have several implications that should be of benefit to the retailing industry and mall management. Developers of malls must develop their mall more than simply a place for buying products. As such, mall management should make sure that their mall atmospherics offer a mall environment that is pleasing to multiple senses, to ensure it is conducive for shoppers to stay and spend more of their time and money. Mall management must execute strategies to maintain their attraction to younger consumers, perhaps by including stores that are futuristic and offer the most advanced styles or technologies, and appeal to somewhat older adults by offering the tenant, entertainment, and experience mix they will prefer. It is recommended that future research utilize random sampling methods to ensure the generalizability of results.

• 한국의상디자인학회지
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• 제20권4호
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• pp.41-56
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• 2018

The purposes of this study were to investigate preference of Baekje culture relics and to examine purchasing behaviors of fashion cultural products of adolescents. The subjects were 421 adolescents and measuring instruments consisted of Baekje relics preference items, fashion cultural products purchasing behaviors items, and subject' demographic attributions. The data were analyzed by frequency analysis, $x^2$ test, factor analysis, t-test, ANOVA and Duncan's multiple range test using SPSS program. The results were as follows. First, adolescents were more likely to prefer crown ornaments of the King Muryong in Kongju region, and gilt-bronze incense burner and halo in Buyeo region. Second, as fashion cultural products, adolescents were more likely to prefer T-shirts and accessory items, and modern image. As product selection criteria, they considered aesthetics as the most important factor, followed by symbolism and practicality. Adolescents evaluated the resonable purchase price of fashion cultural products as less than 20,000 won for T-shirts, cap & bag, and less than 10,000 won for accessories. The adolescent's satisfaction of fashion cultural products was low, and the main dissatisfaction was high prices, and the lack of practicality and diversity. Third, the preference for Baekje cultural relics and purchasing behaviors of fashion cultural products differed according to age and sex of adolescents. This study showed that fashion culture products for adolescents need to be designed in a modern sense with a unique cultural symbolism, focusing on T-shirts and accessories items. In addition, fashion cultural products companies should established the product development plan considering the characteristics according to the age and sex of adolescents.

• 아태비즈니스연구
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• 제12권3호
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• pp.379-396
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• 2021

Purpose - The purpose of this paper is to study the rational payoff from the standpoint of foreign investors and the government when the government issues GDP-linked bonds to foreign investors. Design/methodology/approach - In this paper, the prices of 12 types of GDP-linked bond structures, which are classified according to the calculation cycle of the rate of change of linked GDP, the currency issued, and whether options are embedded, were evaluated. The Fama-French 3-factor model and the GMM-SDF model are used in the asset pricing model, and domestic and overseas investors used different basis assets. Findings - The KRW premium for US investors is estimated to be 43bp on a quarterly basis and 30bp on an annual basis, respectively, meaning that when the government issues bonds in KRW, the interest rate paid to US investors will be reduced by 30bp to 160bp (annually converted). Using the Fama-French 3 factor model, the KRW premium is the risk premium for the US market beta, meaning that if US investors do not intend to invest in US market beta, it is advantageous to receive an additional interest rate by investing in USD-denominated GDP-linked bonds. Korea's GDP- linked bond give US investors diversified investment utility, so they are willing to incorporate Korean GDP-linked bonds even if -150bp of interest is deducted from the structure issued to Korean investors. And as a result of estimating the value of the option through the GDP-linked bond with options that provides a floor for guaranteeing the principal, the value of the option linked to the annual GDP issued in dollars was the lowest. Research implications or Originality - Issuing dollar-denominated GDP-linked bonds linked to annual GDP with the option of guaranteeing the principal by the government is a way to increase investment opportunities for US investors and achieve financial stability of the government.