• 융합정보논문지
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• 제11권11호
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• pp.10-16
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• 2021

스마트공장의 구현이 널리 확산되면서 IoT장비를 이용한 방대한 양의 빅 데이터를 관련성과 품질 측면에서 우선순위를 지정하여 데이터 효율성을 향상시킬 수 있는 연구 필요성이 제기된다. 원가변동성 추정, 레시피 최적화 등의 관리회계 의사결정에 있어서 빅 데이터의 우선순위를 지정하는 것이 스마트솔루션 성과와 의사결정 효과를 향상시킬 수 있는지를 규명함이 본 연구의 목적이다. 제조데이터를 실시간으로 연계한 ERP, MES 등의 스마트솔루션을 운영하는 국내 중소제조업체 의사결정자 84명의 설문답변을 토대로 경험적 연구 수행 결과, 빅데이터우선순위 설정은 관리회계 의사결정에 긍정적인 영향을 미치는 것으로 분석되었다. 아울러 빅 데이터 우선 순위 지정은 관리회계 의사결정에서 빅 데이터를 사용함으로써 스마트솔루션 성과에 간접적인 영향을 미치는 매개 효과가 있음을 발견하였다. 연구결과를 통하여 경영의사결정과정에서 빅 데이터 간의 연관성을 평가하는 척도를 개발함에 선행연구로서의 기여를 할 수 있을 것이다.

• 융합정보논문지
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• 제11권4호
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• pp.19-25
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• 2021

본 연구는 수작업으로 이루어진 제조현장에서 제조 프로세스를 최적화할 수 있도록 시뮬레이션을 통한 디지털 트윈 구현 방안을 제안하고자 한다. 수작업 모션을 센서로 수집하고 동작 인식에 대하여 반복적인 실험데이터로 제조 프로세스를 최적화하는 지식관리메커니즘을 제안 범위로 한다. 연구목적 달성을 위하여 물류현장 모의실험을 실시하였는데, 작업자의 경험으로 나타난 기초적 지식에 작업시뮬레이션을 반복 경험하게 함으로써 최적화된 디지털 트윈을 생성할 수 있는 방안을 마련하였다. 실험결과, 디지털 트윈을 생성하는 시뮬레이션으로 보다 빠른 시간내에 작업공간 구성과 작업 특성을 생성하여 최적화된 자원을 구성한 결과를 물리시스템으로 전송함으로써 제조 프로세스의 지속적 개선이 가능한 것으로 파악되었다.

• 산업경영시스템학회지
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• 제41권4호
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• pp.238-247
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• 2018

This paper considers the problem of scheduling loading and unloading operations of a crane in a railway terminal motivated from rail-road container transshipment operations at Uiwang Inland Container Depot (ICD). Unlike previous studies only considering the total handling time of containers, this paper considers a bi-criteria objective of minimizing the weighted sum of the total handling time and tenant service time. The tenant service time is an important criterion in terms of terminal tenants who are private logistics companies in charge of moving containers from/to the terminal using their trucks. In the rail-road container shipment yard, the tenant service time of a tenant can be defined by a time difference between beginning and finishing loading and unloading operations of a crane. Thus, finding a set of sequences and time of the crane operations becomes a crucial decision issue in the problem. The problem is formulated as a nonlinear program which is improved by linearizing a nonlinear constraint in the model. This paper develops a genetic algorithm to solve the problem and performs a case study on the Uiwang ICD terminal. Computational experiment results show that the genetic algorithm shows better performance than commercial optimization solvers. Operational implications in terms of tenants are drawn through sensitivity analyses.

• 한국융합학회논문지
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• 제10권7호
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• pp.23-31
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• 2019

2016년 한국에 미군의 사드 미사일이 배치된 이후 중국으로부터 단체관광은 전면 중단되었다. 이후 중국인의 한국 관광은 개인 중심의 여행일정으로 이루어지고 있다. 본 연구에서는 2018년 1월부터 12월 까지 온라인 여행노트를 통해 데이터를 수집하고, 소셜 네트워크 분석을 활용하여 개별방문 중국인의 계절별 한국관광 여정 특성을 분석하였다. 분석 결과 서울은 중국인의 한국여행 허브이며 개별 방문 중국인의 주요 방문지는 서울, 부산, 제주도, 경주 및 강릉에 집중되어 있고 계절에 따라 큰 차이가 있는 것으로 나타났다. 연구 결과는 개별 중국인의 한국 관광을 위한 관광코스의 개발, 관광 서비스 제공 및 관광 시설배치의 최적화를 위한 기초자료로 활용될 수 있다. 향후 연구는 여행 방문지와 관광명소 사이의 이동 교통방식을 연구하여 관광 일정 계획 설계에 참고를 제공할 수 있다.

• International Journal of Computer Science & Network Security
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• 제21권3호
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• pp.198-205
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• 2021

For twenty years, in the EU there has been a trend of a lack of maritime infrastructure and a redundance of the road one, which has a negative impact on the economy. The intermodal transport market structure in the EU has not changed over the past ten years. The stability of transport systems due to the lack of changes in the transport market remains under threat, affecting supply chains and networks through the optimization of warehousing and transportation costs. The research methodology is based on a quantitative assessment of cause-and-effect relations between economic growth and transport and logistics in the EU. A statistical analysis of security indicators, intermodal and modal transport, international trade in goods within the EU and in the world trade in goods, the dynamics of GDP of the EU countries, the level of openness of the EU economy, investment and maintenance costs of different modes of transport and infrastructure has been carried out. The results show that in 2000- 2010 there were positive changes in the transport and logistics infrastructure of the EU, which had a positive effect on trade, openness of the economy of the EU, GDP growth. However, at that time, negative effects of environmental impact and the load on road and rail transport were accumulating. Investment in different modes of transport is limited, and technical maintenance and infrastructure maintenance costs form a significant part of GDP of the EU. A slowdown in economic growth leads to budget constraints and infrastructure financing gap. As a result, the freight and passenger intermodal and modal transport market structure remains virtually unchanged. The load on rail and road transport remains stable, despite the reduced level of transport hazards. Transport productivity has declined over the past ten years. Herewith, the intensification of trade and the openness of the EU economies require constant modernization and innovative renewal. The EU policy in this direction remains normative, uncontrolled, which is reflected in investment differences within the EU and maintenance costs.

• Journal of Ginseng Research
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• 제46권3호
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• pp.367-375
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• 2022

Background: Short-term hydroponic-cultured ginseng (sHCG), which is 1-year-old ginseng seedlings cultivated for 4 weeks in a hydroponic system, is a functional food item with several biological effects. However, the optimal extraction conditions for sHCG, and the bioactivity of its extracts, have not been evaluated. Methods: Chlorogenic acid (CGA) and ginsenoside contents were evaluated in sHCG, white ginseng (WG), and red ginseng (RG) using high-performance liquid chromatography. Response surface methodology (RSM) was used to optimize the extraction conditions (temperature and ethanol concentration) to maximize the yield of dry matter, CGA, and four ginsenosides (Re, Rg₁, Rb₁, and Rd) from sHCG. The optimal extraction conditions were applied to pilot-scale production of sHCG extracts. The expression levels of tumor necrosis factor (TNF)-α/interferon (IFN)-γ-induced thymic and activation-regulated chemokines (TARC/CCL17) were measured after treatment with sHCG, WG, and RG extracts, and the effects of their bioactive compounds (CGA and four ginsenosides) on human skin keratinocytes (HaCaTs) were evaluated. Results: CGA and four ginsenosides, which are bioactive compounds of sHCG, significantly inhibited TNF-α/IFN-γ-induced TARC/CCL17 expression. The optimal sHCG extraction conditions predicted by the RSM models were 80 ℃ and 60% ethanol (v/v). The sHCG extracts produced at the pilot scale under optimal conditions greatly alleviated TNF-α/IFN-γ-induced TARC/CCL17 production compared with WG and RG extracts. Conclusions: Pesticide-free sHCG extracts, which contain high levels of CGA and the ginsenosides Re, Rg₁, Rb₁, and Rd as bioactive compounds, may have therapeutic potential for atopic diseases.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1674-1685
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• 2022

The ball valve is an important device in the pipeline transportation system of nuclear power plants. Its operational stability and safety directly affect the normal working of nuclear power plants. In this study, the transient numerical simulation of the opening and closing process of a ball valve was conducted on the basis of the flow interruption capability experiment of the ball valve by using the moving mesh method and inlet and outlet variable boundary conditions. The flow rate and pressure difference with time of the opening and closing process of the ball valve were studied. The internal flow characteristics of the ball valve under different relative openings were analyzed in conjunction with the typical back-step flow structure. Results show that the transient numerical results agree well with the experimental results. The internal flow characteristics of the ball valve are similar at the same opening during opening and closing process. At small opening, the spool and outlet channels easily form a back-step flow structure. The disappearance and generation of backflow vortices during opening and closing occur at 85% opening and 75% opening, respectively. With the decrease in opening degree, the difference in vortex core area in the flow channel of the ball valve spool in the opening and closing process gradually appears. The research results provide some reference value for the design and optimization of ball valves.

• 품질경영학회지
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• 제50권4호
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• pp.701-716
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• 2022

Purpose: This study aims to predict the dry cargo transportation market economy. The subject of this study is the BDI (Baltic Dry Index) time-series, an index representing the dry cargo transport market. Methods: In order to increase the accuracy of the BDI time-series, we have pre-processed the original time-series via time-series decomposition and data augmentation techniques and have used them for ANN learning. The ANN algorithms used are Multi-Layer Perceptron (MLP), Recurrent Neural Network (RNN), and Long Short-Term Memory (LSTM) to compare and analyze the case of learning and predicting by applying time-series decomposition and data augmentation techniques. The forecast period aims to make short-term predictions at the time of t+1. The period to be studied is from '22. 01. 07 to '22. 08. 26. Results: Only for the case of the MAPE (Mean Absolute Percentage Error) indicator, all ANN models used in the research has resulted in higher accuracy (1.422% on average) in multivariate prediction. Although it is not a remarkable improvement in prediction accuracy compared to uni-variate prediction results, it can be said that the improvement in ANN prediction performance has been achieved by utilizing time-series decomposition and data augmentation techniques that were significant and targeted throughout this study. Conclusion: Nevertheless, due to the nature of ANN, additional performance improvements can be expected according to the adjustment of the hyper-parameter. Therefore, it is necessary to try various applications of multiple learning algorithms and ANN optimization techniques. Such an approach would help solve problems with a small number of available data, such as the rapidly changing business environment or the current shipping market.

• 한국가스학회지
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• 제26권2호
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• pp.39-48
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• 2022

중대산업사고를 일으킬 수 있는 화재, 폭발, 누출과 같은 사고를 사전에 예방할 수 있는 설비 중 하나인 가스감지기에 적용하고 있는 국내 가스감지기 설치 기준은 유해화학물질의 대기 중 거동 특성을 고려하지 않은 설치 기준을 적용하고 있어 그 기술적 근거가 부족하다고 볼 수 있다. 따라서 본 연구에서는 화학공장에서 주로 사용하는 설비별 누출공의 크기와 유해화학물질의 관심 농도에 따른 확산 거리를 분석, 이를 토대로 하여 물질 별 가스감지기 최적 설치거리를 제시하였다. 본 연구에서 제시한 방법을 이용하여 보다 경제적이고 효과적인 가스감지기 설치를 기대할 수 있으며, 나아가 중대산업사고를 예방하는데 도움이 될 것으로 기대할 수 있다.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1587-1592
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• 2023

Time-encoded imagers (TEI) are important class of instruments to search for potential radioactive sources to prevent illicit transportation and trafficking of nuclear materials and other radioactive sources. The energy of the radiation cannot be known in advance due to the type and shielding of source is unknown in practice. However, the response function of the time-encoded imagers is related to the energy of neutrons or gamma-rays. An improved image reconstruction method based on MLEM was proposed to correct for the energy induced response difference. In this method, the count vector versus time was first smoothed. Then, the preset response function was adaptively corrected according to the measured counts. Finally, the smoothed count vector and corrected response were used in MLEM to reconstruct the source distribution. A one-dimensional dual-particle time-encode imager was developed and used to verify the improved method through imaging an Am-Be neutron source. The improvement of this method was demonstrated by the image reconstruction results. For gamma-ray and neutron images, the angular resolution improved by 17.2% and 7.0%; the contrast-to-noise ratio improved by 58.7% and 14.9%; the signal-to-noise ratio improved by 36.3% and 11.7%, respectively.