• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.411-414
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• 2015

The purpose of this study is to conduct a comparative analysis between Korea and the United States of the supply process of unit modular housing at both the factory production phase and the transportation and lifting phase, as part of an attempt to invigorate the unit modular housing market in Korea. Unlike the practice in the United States, one of Korea's unique characteristics is that the floor is constructed with reinforced concrete and hot water heating system. To do this, the wet method in Korea is used that includes concrete placement, curing and constructing hot water floor heating system at the factory production phase, which results in a longer production time and also requires the lifting of heavier loads. In the United States, interior and exterior finishing works of modular housing are performed by different companies, and the distance between the unit module factory and the construction site is quite far. This kind of dualized production structure may cause confusion when it comes to schedule management, procurement management, and stock management. Moreover, problems caused by external environmental factors such as wind and rainfall were reported in the course of long-distance transportation. The results of this case comparison are expected to provide fundamental data that will reduce the amount of trial and error in the unit module production, transportation and lifting work in Korea, which has a comparatively small number of unit modular housing cases.

• 농촌계획
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• 제19권1호
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• pp.123-135
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• 2013

The purpose of this study is to investigate industry-wise employment growth factors in rural areas. Regional economic vitalization is sensitive to internal and external interaction changes among various industrial and occupational sectors. Thus, rural regional economic vitalization requires a comprehensive approach in analyzing industry-dependent employment structures and growth factors in rural areas. However, research conducted thus far has mostly focused on agriculture and farmers. Considering the evidence that rural communities continue to be stagnant and 80% of the rural population is engaged in nonagricultural activities, it becomes necessary to review industry-specific employment change factors in rural areas. This study targeted 5 counties in Chungnam. The results revealed that agriculture, forestry, and fisheries occupied the foremost positions with regard to population employed and regional GRDP share. The influence of national growth on employment and business variation effects was as high as 98.1% and 78.6%, respectively, thus demonstrating the high likelihood of rural economy to be influenced by external factors. Growth in the public sector appeared to support employment structure. Moreover, wholesale and retail businesses, constituting 14.4% of employment in rural areas, showed a strong trend toward degeneration, to the extent that difficulties have been forecasted for the supply of goods and services essential for basic livelihood of the rural residents. The implications based on the above observations need to be considered for policy-making to ensure that industrial structure is modified on the basis of internal demand of the region, and support for small businesses is integrated in rural area development projects.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.712-713
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• 2015

In recent years, the bid-rigging in public construction markets has been treated as a critical issue in Fair Trade Commission. The investigation revealed that the collusion was implemented extensively in every area from the material supply to the construction service of general contractors. This study reviewed the causes of the bid-rigging in public construction projects, and proposed the improvement plan to eradicate bad practices. Firstly, the causes and purposes of bid-rigging were categorized into two types of internal factors from construction companies and external environment factors influencing business activities. Secondly, the system development method was explained to detect the signs of bid-rigging based on the technical proposal documents in open tender. The detection systems of repetitive public owner also provide the function of sharing data on the companies and cases to violate the fair trade regulation. In addition, the problems and improvement direction of public procurement policies were discussed.

• 한국지반환경공학회 논문집
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• 제12권12호
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• pp.13-20
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• 2011

외수압에 의한 강관 라이닝 좌굴 사례를 조사, 평가하여 강관 라이닝의 안전성에 미치는 요소 및 그 중요도를 산정하고자 하였다. 대상터널은 ${\bigcirc}{\bigcirc}$광역상수도 도수시설인 직경 2m의 수로터널로서 터널 라이닝은 내부의 강관 라이닝과 배면의 뒷채움 콘크리트로 구성되어 있다. 두 개의 수로터널에서 발생된 강관 라이닝 좌굴 손상을 대상으로 손상의 형태 및 설계 조건을 상세하게 조사하였다. 좌굴 손상에 적용 가능한 좌굴 안전성 평가방법을 기존의 문헌 자료를 참조하여 선정하였으며, 손상에 대한 조사결과와 비교하였다. 또한 본 지역의 수리지질학적인 특성이 좌굴 손상에 미치는 영향을 검토하였다. 연구결과 수리지질학적 지층특성뿐만 아니라 터널 라이닝의 적절한 시공이 강관 라이닝의 좌굴에 영향을 미치는 중요한 요소이며, 외수압의 크기 결정은 수리지질 특성에 따라 산정되어야 하는 것을 알 수 있었다. 기존 손상 사례에 대한 연구는 압력 수로터널의 강관 라이닝에 대한 설계, 시공 및 유지관리 기간 중의 문제점 및 개선사항을 도출하는데 활용될 수 있을 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권3호
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• pp.528-550
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• 2024

Warehousing demand prediction is an essential part of the supply chain, providing a fundamental basis for product manufacturing, replenishment, warehouse planning, etc. Existing forecasting methods cannot produce accurate forecasts since warehouse demand is affected by external factors such as holidays and seasons. Some aspects, such as consumer psychology and producer reputation, are challenging to quantify. The data can fluctuate widely or do not show obvious trend cycles. We introduce a new model for warehouse demand prediction called MAGRU, which stands for Multi-layer Attention with GRU. In the model, firstly, we perform the embedding operation on the input sequence to quantify the external influences; after that, we implement an encoder using GRU and the attention mechanism. The hidden state of GRU captures essential time series. In the decoder, we use attention again to select the key hidden states among all-time slices as the data to be fed into the GRU network. Experimental results show that this model has higher accuracy than RNN, LSTM, GRU, Prophet, XGboost, and DARNN. Using mean absolute error (MAE) and symmetric mean absolute percentage error(SMAPE) to evaluate the experimental results, MAGRU's MAE, RMSE, and SMAPE decreased by 7.65%, 10.03%, and 8.87% over GRU-LSTM, the current best model for solving this type of problem.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.342-349
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• 2017

본 연구는 한국사회적기업진흥원의 2015년 219개 사회적기업 경영공시자료를 중심으로 다중선형 회귀분석기법을 활용하여, 사회적기업의 사회적 성과와 경제적 성과에 영향을 미치는 조직특성요인을 검증하고, 사회적 성과와 경제적 성과 간의 상관관계를 분석하였다. 이러한 연구결과는 다음과 같다. 첫째, 사회적기업의 조직특성 중 인증연수 및 외부지원 수혜액이 사회적기업의 사회적 성과인 취약계층 고용에 모두 정(+)의 영향을 미치는 것으로 나타났으며, 조직형태와 인증유형, 사회서비스 업종(제공 유형) 등의 변수들은 통계적으로 유의미한 영향을 주지 못하는 것으로 분석되었다. 둘째, 사회적기업의 조직특성 중 인증연수와 외부지원 수혜액이 사회적기업의 경제적 성과인 매출액에 정(+)의 영향을 미치나, 조직형태의 경우는 부(-)의 영향을 미치는 것으로 나타났으며, 인증유형과 사회서비스 업종(제공 유형) 등의 변수들은 통계적으로 유의미한 영향을 주지 못하는 것으로 나타났다. 셋째, 사회적기업의 사회적 성과인 취약계층 고용과 경제적 성과인 매출액 간의 상관관계를 분석한 결과, 사회적기업의 매출액과 취약계층 고용이 서로 선순환의 관계에 있는 정(+)의 상관관계를 가지는 것으로 분석되었다. 이러한 분석결과는 인증연수별로 정부의 사회적기업 육성 및 지원정책을 다양화하여 사회적 성과와 경제적 성과를 극대화함으로써 사회적기업의 자립과 지속가능성을 도모할 수 있음을 시사하고 있다.

• Journal of Information Technology Applications and Management
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• 제22권1호
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• pp.153-163
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• 2015

The purpose of this study is to investigate the relationship among factors that expand the win-win growth between domestic finished goods-making manufacturers and subcontractors. One-hundred twenty six firms participated for this study and were used for the data analysis. As a result of analysis, first, it was found that the win-win growth between first-tier suppliers and second-tier suppliers has positive effects on the win-win growth made by second-tier suppliers helping the third-tier suppliers. Second, it was found that the win-win growth policies supported by the government for the positive relationship between first-tier suppliers and second-tier suppliers for the finished goods-making manufacturers have positive effects on the win-win growth between second-tier suppliers and third-tier suppliers. Third, the results also showed that the win-win growth between second-tier suppliers and third-tier suppliers has a positive influence both on the financial and on the non-financial performances of the second-tier suppliers. Based on the results of this study, it is recommended to (1) construct infrastructure by sector through partnership between finished goods-making manufacturers and subcontractors, (2) draw in active support through the governmental win-win growth policies, (3) induce increasing productivities through information sharing, manpower support, technical support and educational support, and (4) strengthen and cultivate the culture of the small- and medium-sized companies.

• 무역학회지
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• 제47권2호
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• pp.133-154
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• 2022

The Baltic Capesize Index (BCI), which is used as an indicator for marine transportation of steel raw materials, is one of the key economic indexes for managing the risk of loss due to rapid market fluctuations when steel companies establish business strategies and procuring plans for raw materials. Still, the conditions of supply and demand of steel raw materials has been extremely affected by volatility shocks from drastic events like the financial crisis such as the Lehman Brothers incident and changes in the external environment such as COVID-19. And, especially since the 2008 financial crisis, endeavors to predict the market conditions of the steel raw material is becoming more and more arduous for the deepening uncertainty and increased volatility of BCI, which has been used as a leading indicator of the real economy. This study investigates the correlation between the steel raw material market and the marine transportation market by estimating the spillover effect of information between markets. The vector error correction model (VECM) was used to analyze information transfer based on the correlation between the BCI and crude steel production, capesize fleet supply, raw material price, and cargo volume.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1334-1339
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• 2020

This paper presents an empirical and comprehensive forecasting analysis of the uranium price. Prices are generally difficult to forecast, and the uranium price is not an exception because it is affected by many external factors, apart from imbalances between demand and supply. Therefore, a systematic analysis of multiple forecasting methods and combinations of them along repeated forecast origins is a way of discerning which method is most suitable. Results suggest that i) some sophisticated methods do not improve upon the Naïve's (horizontal) forecast and ii) Unobserved Components methods are the most powerful, although the gain in accuracy is not big. These two facts together imply that uranium prices are undoubtedly subject to many uncertainties.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.299-304
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• 2008

Catenary and Pantograph are a power supply devices for electric trains and shall be steadily contacted. Rail catenary must be installed precisely and managed for stable train operations. But external factors such as weathers, nature, etc., or aging affect catenary geometry. Changed catenary height causes high voltage spark or instant electric disconnection. Big spark and disconnection damage pantograph shoe and catenary coating and might interrupt rail operations. To prevent a big scale spark or electric disconnection catenary maintenance shall be required with catenary geometry measurement systems. In this paper, we describe the development of catenary height and stagger measurement system. The catenary height and stagger measurement system uses Acuity company's AR4000 Range Finder for distance measurement and AccuRange Line Scanner for degree measurement. This system reports suspicious overhead line sections with excessive height and stagger variance.