• 한국응용과학기술학회지
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• 제38권2호
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• pp.618-627
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• 2021

기능성 화장품이라 함은 피부미백, 주름개선, 자외선차단 등 특정한 기능을 가지고 피부에 효과를 주는 화장품을 말했다. 그런데 2017년 이후 기능성 화장품의 품목이 확대되었다. 대한민국의 기능성 화장품 산업은 미백, 주름, 자외선 차단 제품에 머물고 새로운 기능성 제품의 개발은 미비한 상태이다. 또한 코스메슈티컬과 메디컬 화장품을 비롯한 고기능성 화장품도 아직 정립되지 않은 상태이다. 그리고 국외에 수출실적 순위는 프랑스가 가장 높았고 미국, 독일 순으로 나타났다. 프랑스는 화장품 산업 업계 1위 국가답게 바이오 공업과 기능성 소재에서 메커니즘 중심의 기능성 화장품을 강조하고 있고 미국은 럭셔리 프리미엄 제품에 수요도가 높았으며 독일은 바이오 하이테크 기술에 주목하고 있다. 이처럼 한국도 신흥 산업에 적용할 수 있는 기능성 화장품들의 새로운 소재들을 개발하고 정치와 경제가 뒷받침 되어 연구에 더 집중할 수 있는 환경이 갖춰져 다양한 기능성 화장품 산업 등을 발전시켜 나아가야 할 것이다.

• 정보보호학회논문지
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• 제31권6호
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• pp.1247-1260
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• 2021

최근, 무선 센서 네트워크에서 더욱 효율적인 노드의 에너지 관리를 위해 센서 데이터를 대신 수집해주는 모바일 싱크 노드에 관한 연구가 있었다. 대표적인 모바일 싱크 노드로는 UAV (Unmanned Aerial vehicle)가 사용되며, 학계에서는 최적의 UAV 경로를 계산하는 알고리즘을 제시하는 위주로 IoD (Internet of Drones) 환경의 급격한 발전을 만들어냈다. 동시에, 보안 관점에서 다수의 노드와 세션키를 효율적으로 만들어야 하는 IoD의 특성에 맞춰 상호 인증 및 안전한 키 교환을 목표로 하는 기법들이 몇몇 제시되었다. 하지만, 모바일 싱크 노드 환경에서의 안전한 통신을 제안한 대부분 논문은 종단 간 데이터 프라이버시가 지켜지지 않았다. 따라서 본 논문에서는 모바일 싱크 노드와 센서 노드 간 인증부터 모바일 싱크 노드가 센서 데이터를 기지국까지 안전하게 중계하는 통합적 보안 모델을 처음으로 제안한다. 또한, 제안한 프로토콜의 안전성을 비공식적으로 입증하고 알려진 다양한 공격으로부터 안전함을 보인다. 마지막으로 기존에 제시된 IoD 환경에서 안전한 키 교환을 주제로 한 기법들과 통신 오버헤드를 비교해 본 논문에서 제시한 기법이 우수하다는 것을 보여준다.

• 한국기계가공학회지
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• 제21권4호
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• pp.60-69
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• 2022

To keep pace with Industry 4.0, it is imperative for companies to redesign their working environments by adopting robotic automation systems. Automation lines are facilitating the latest cutting-edge technologies, such as 3D vision and industrial robots, to outdo competitors by reducing costs. Considering the nature of the manufacturing industry, a time-saving workflow and smooth linkwork between processes is vital. At Dellics, without any additional new installation in the automation lines, only a few improvements to the working process could raise productivity. Three requirements are the development of gripping technology by utilizing a 3D vision system for the recognition of the material shape and location, research on lighting projectors to target long distances and high illumination, and testing of algorithms/software to improve measurement accuracy and identify products. With some of the functional requisites mentioned above, improved robotic automation systems should provide an improved working environment to maximize overall production efficiency. In this article, the ways in which such a system can become the groundwork for establishing an unmanned working infrastructure are discussed.

• 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.

• Wind and Structures
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• 제34권5호
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• pp.395-405
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• 2022

Tornado-induced damages to high-rise buildings and low-rise buildings are quite different in nature. Tornado losses to high-rise buildings are generally associated with building envelope failures while tornado-induced damages to low-rise buildings are usually associated with structural or large component failures such as complete collapses, or roofs being torn off. While studies of tornado-induced structural damages tend to focus mainly on low-rise residential buildings, transmission towers, or nuclear power plants, the current rapid expansion of city centers and development of large-scale building complexes increases the risk of tornadoes impacting tall buildings. It is, therefore, important to determine how tornado-induced load affects tall buildings compared with those based on synoptic boundary layer winds. The present study applies an experimentally simulated tornado wind field to the Commonwealth Advisory Aeronautical Research Council (CAARC) building and estimates and compares its pressure coefficient effects against the Atmospheric Boundary Layer (ABL) flow field. Simulations are performed at the Wind Engineering, Energy and Environment (WindEEE) Dome which is capable of generating both ABL and tornadic winds. A model of the CAARC building at a scale of 1:200 for both ABL and tornado flows was built and equipped with pressure taps. Mean and peak surface pressures for TLV flow are reported and compared with the ABL induced wind for different time-averaging. By following a compatible definition of the pressure coefficients for TLV and ABL fields, the resulting TLV pressure field presents a similar trend to the ABL case. Also, the results show that, for the high-rise building model, the mean and 3-sec peak pressures are larger for the ABL case compared to the TLV case. These results provide a way forward for the code implementation of tornado-induced pressures on high-rise buildings.

• Steel and Composite Structures
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• 제41권5호
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• pp.761-773
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• 2021

This study presents a 3D non-linear finite element (FE) assessment of dynamic soil-structure interaction (SSI). The numerical investigation has been performed on the time domain through a Finite Element (FE) system, while considering the nonlinear behavior of soil and the multi-directional nature of genuine seismic events. Later, the FE outcomes are analyzed to the recorded in-situ free-field and structural movements, emphasizing the numerical model's great result in duplicating the observed response. In this work, the soil response is simulated using an isotropic hardening elastic-plastic hysteretic model utilizing HSsmall. It is feasible to define the non-linear cycle response from small to large strain amplitudes through this model as well as for the shift in beginning stiffness with depth that happens during cyclic loading. One of the most difficult and unexpected tasks in resolving soil-structure interaction concerns is picking an appropriate ground motion predicted across an earthquake or assessing the geometrical abnormalities in the soil waves. Furthermore, an artificial neural network (ANN) has been utilized to properly forecast the non-linear behavior of soil and its multi-directional character, which demonstrated the accuracy of the ANN based on the RMSE and R² values. The total result of this research demonstrates that complicated dynamic soil-structure interaction processes may be addressed directly by passing the significant simplifications of well-established substructure techniques.

• 한국콘텐츠학회논문지
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• 제22권9호
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• pp.283-297
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• 2022

본 연구는 중국기업의 '일대일로' 연선 국가에 대한 직접투자 전략과 구조를 더닝(Dunning)의 OLI 패러다임 관점에서 분석하였다. 중국기업의 '일대일로' 연선 국가에 대한 투자는 크게 두 가지 전략적 목적에서 추진 되었다. 하나는 '일대일로' 연선 국가의 자원보유 특성상 에너지자원 확보를 위한 투자이고, 또 다른 하나는 중국 국내경제의 문제인 과잉설비 문제를 해결하기 위한 이전(移轉) 투자이다. 중국기업의 이러한 '일대일로' 연선 국가에 대한 투자는 더닝이 OLI 패러다임에서 제기하고 있는 투자 결정 조건, 즉 소유권 우위와 지역특유의 우위 그리고 내부화 우위를 갖춘 가운데 투자를 진행한 것으로 평가된다. 다만 차이가 있다면, 이 지역이 갖는 특수성으로 인해 자원보유 현황 및 제도적 환경의 영향 외에 국제관계의 이해관계 구도, 종교적 갈등 문제와 문화적 이질성 그리고 이 지역 국가들의 중국기업에 대한 인식의 문제 등의 영향으로 투자국가와 투자방식 그리고 투자업종을 달리하고 있다는 점이다.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.57-66
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• 2022

The aim of the article is to investigate socio-political processes in Ukraine on the basis of institutional and behavioral approaches, in particular their regulatory and informational support. Methodology. To determine the nature and content of sociopolitical processes, the following approaches have been used: 1. Institutional approach in order to analyze the development of Ukraine's political institutions. 2. The behavioral approach has been used for the analysis of socio-political processes in Ukraine in the context of political behavior of citizens, their political activity which forms the political culture of the country. Results. The general features of the socio-political situation in Ukraine are as follows: the formed model of government, which can be conditionally described as "presidential"; public demand for new leaders remains at a high level; the society has no common vision of further development; significant tendency of reduction of real incomes of a significant part of the society and strengthening of fiscal pressure on businessmen will get a public response after some time. Increasing levels of voice, accountability, efficiency of governance and the quality of the regulatory environment indicate a slow change in the political system, which will have a positive impact on public sentiment in the future. At the same time, there has been little change in the quality of Ukraine's institutions to ensure political stability, the rule of law and control of corruption. There are no cardinal changes in the development of the institution of property rights, protection of intellectual rights, changes in the sphere of ethics and control of corruption. Thus, Ukraine's political institutions have not been able to bring about any change in the social-political processes. Accordingly, an average level of trust and confidence of citizens in political institutions and negative public sentiment regarding their perception and future change can be traced in Ukraine.

• 한국재료학회지
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• 제32권5호
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• pp.264-269
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• 2022

Ti₃C₂T_x MXene, which is a representative of the two-dimensional MXene family, is attracting considerable attention due to its remarkable physicochemical and mechanical properties. Despite its strengths, however, it is known to be vulnerable to oxidation. Many researchers have investigated the oxidation behaviors of the material, but most researches were conducted at high temperatures above 500 ℃ in an oxidation-retarding environment. In this research, we studied changes in the structural and electrical properties of Ti₃C₂T_x MXene induced by low-temperature heat treatments in ambient conditions. It was found that a number of TiO₂ particles were formed on the MXene surface when it was mildly heated to 200 ℃. Heating the material to higher temperatures, up to 400 ℃, the phase transformation of Ti₃C₂T_x MXene to TiO₂ was accelerated, resulting in a TiO₂/Ti₃C₂T_x hybrid. Consequently, the metallic nature of pure Ti₃C₂T_x MXene was transformed to semiconductive behavior upon heat-treating at ≥ 200 ℃. The results of this research clearly demonstrate that Ti₃C₂T_x MXene may be easily oxidized even at low temperatures once it is exposed to air.

• 대한지구과학교육학회지
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• 제16권1호
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• pp.87-102
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• 2023

이 연구의 목적은 지역사회의 시민 강사 등이 지역사회 문제에 기반한 초등학생용 기후변화교육 프로그램을 개발할 때 반드시 포함해야 할 내용을 분석틀로 제안하는 것으로, 이 분석틀의 개발을 위해 현장 및 기후환경교육 전문가 24명에게 총 7번의 자문을 받았다. 최종 분석틀은 문항별 내용타당도는 I-CVI와 S-CVI 계수로, 전문가 패널 간 신뢰도는 Fleiss' Kappa 계수를 통계적으로 검증하였다. 최종 분석틀은 3개의 분석 영역(프로그램 목적 - 프로그램 내용 - 프로그램 평가)과 7개의 분석 항목, 7개의 분석 지표와 세부 설명으로 구분하여 개발했다. 특히 분석 지표에 대한 세부 설명란을 추가하여 내용타당도와 신뢰도를 높임으로써 객관적인 분석틀로서의 성격을 확고히 했다. 이 연구에서 제안한 지역사회 기반 초등학생용 기후변화교육 프로그램 분석틀이 체계적인 프로그램 개발에 도움이 되길 기대한다.