• Geomechanics and Engineering
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• 제34권2호
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• pp.115-124
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• 2023

By conducting three-dimensional simulation with consideration of small-strain characteristics of soil stiffness, the effects of excavation geometry and tunnel cover to diameter ratio on deformation mechanisms of an existing tunnel located either at a side of basement or directly underneath the basement were systematically studied. Field measurements were used to verify the numerical model and model parameters. For basement excavated at a side of an existing tunnel, the maximum settlement and horizontal displacement of the tunnel are always observed at the tunnel springline closer to basement and tunnel crown, respectively, regardless of basement geometry. By increasing basement length and width by five times, the maximum movements of tunnel located at the side of basement and directly underneath the basement increase by 450% and 186%, respectively. Obviously, tunnel movements are more sensitive to basement length rather than basement width. For basement excavated at a side of an existing tunnel, tunnel movements at basement centerline become stable when basement length reaches 10 H_e (i.e., final excavation depth). Moreover, tunnel heaves due to overlying basement excavation become stable when the normalized basement length (L/H_e) is larger than 8.0. As tunnel cover to diameter ratio varies from 2.5 to 3.0, the maximum heave and tensile strain of tunnel due to overlying basement excavation decrease by up to 41.0% and 44.5%, respectively. If basement length is less than 8 H_e, the assumption of plane strain condition of basement-tunnel interaction grossly overestimates tunnel movements, and ignores tensile strain of tunnel along its longitudinal direction. Thus, three-dimensional numerical analyses are required to obtain a reasonable estimation of tunnel responses due to adjacent and overlying basement excavations in clay.

• 한국지형학회지
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• 제28권2호
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• pp.1-13
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• 2021

It is very important to secure sufficient river maintenance flow for the ecosystem, since the ecosystem in the downstream section of the dam is greatly affected by the stream maintenance flow from the dam. However, the amount of discharge from the Seomjingang Dam is decreasing year by year, this study estimated the ecological flow required for the downstream section of the Seomjingang Dam, which is known as the habitat of the endangered Acheilognathus somjinensis, in order to secure the river flow of the Seomjingang Dam. For this purpose, the proper discharge was calculated using the PHABSIM model, which is a hydrological survey and physical habitat simulation method, and the proper discharge of other fish species were also comprehensively reviewed. As a result of this study, the current river maintenance flow at the Seomjingang Dam partially satisfies the ecological maintenance flow including the Acheilognathus somjinensis in the downstream section of the Seomjingang Dam. However, this is recognized as the minimum discharge to maintain the ecology in the downstream section of the Seomjingang Dam, and it would be more desirable to secure larger river maintenance flow than this. This study can contribute the determination of the river maintenance flow of the Seomjingang Dam by proposing the river maintenance flow considering the fish habitat environment in the river.

• 한국지반신소재학회논문집
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• 제22권4호
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• pp.63-71
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• 2023

남·북극을 포함한 극한지는 풍부한 자원이 매장되어 있지만 접근성이 어렵고, 국내와 전혀 다른 건설 환경 때문에 자원개발 사업 추진에 많은 제약이 있다. 최근 지구온난화로 극한지의 접근성이 용이해짐에 따라 자원개발 플랜트 건설 수요가 증가하고 있다. 이러한 지역에서의 자원개발 건설 활동을 위해서는 사업추진의 리스크를 최소화할 수 있도록 사전 입지 분석이 필요하다. 본 논문에서는 극한지 건설 활동에서 고려해야 할 주요 요인들을 분석하여, 공간정보(GIS, Geographic Information System) 기반의 건설환경 플랫폼 및 최적 입지 선정 시스템을 새롭게 개발하였다. 오일샌드 개발이 활발하게 진행되고 있는 캐나다 앨버타주(Alberta) 대상으로 개발 시스템을 적용한 결과, 현재 운용되고 있는 오일샌드 플랜트 채굴 지역과 일치함을 확인하였다.

• Smart Structures and Systems
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• 제32권5호
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• pp.319-338
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• 2023

The study presents a new hybrid data-driven method by combining radial basis functions neural networks (RBF-NN) with the Jaya algorithm (JA) to provide effective structural health monitoring of arch dams. The novelty of this approach lies in that only one user-defined parameter is required and thus can increase its effectiveness and efficiency, as compared to other machine learning techniques that often require processing a large amount of training and testing model parameters and hyper-parameters, with high time-consuming. This approach seeks rapid damage detection in arch dams under dynamic conditions, to prevent potential disasters, by utilizing the RBF-NNN to seamlessly integrate the dynamic elastic modulus (DEM) and modal parameters (such as natural frequency and mode shape) as damage indicators. To determine the dynamic characteristics of the arch dam, the JA sequentially optimizes an objective function rooted in vibration-based data sets. Two case studies of hyperbolic concrete arch dams were carefully designed using finite element simulation to demonstrate the effectiveness of the RBF-NN model, in conjunction with the Jaya algorithm. The testing results demonstrated that the proposed methods could exhibit significant computational time-savings, while effectively detecting damage in arch dam structures with complex nonlinearities. Furthermore, despite training data contaminated with a high level of noise, the RBF-NN and JA fusion remained the robustness, with high accuracy.

• 한국의류산업학회지
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• 제25권5호
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• pp.593-602
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• 2023

This study aimed to facilitate the use of virtual technologies such as sewing, appearance, and material expression in 3D virtual wear programs. For product production and education, we expounded how to express the shoulder shape and silhouette of sleeve-expanded power shoulder jackets. Two designs of sleeve-expanded power shoulder jackets were selected, and virtual jackets were produced using a virtual avatar based on the body dimensions of female subjects in their 20s. The essential purpose of a 3D virtual power shoulder jacket is to express the shoulder angle rise and shoulder width, which are much wider than the avatar's shoulder. Therefore, the virtual pad values were adjusted for the collision and rendering of each thickness. In addition, the position and angle of the virtual pads were controlled through simulation. Appearance similarity was evaluated using photographic data and the virtual jackets. For the set-in sleeve virtual power shoulder jacket, the wrinkle expressions of the torso and sleeve were rated as moderate, and material expression was slightly insufficient. The similarity of some ease and width items of the torso was tightly expressed, and the overall appearance, positions of lines, and details of jackets were rated high, especially at the neck and sleeve shapes. In the case of the kimono virtual power shoulder jacket, the expressions of the torso wrinkles and buttons were slightly lower; however, the overall similarity, basic lines, ease, shoulder and neck details, and material expression of the virtual jackets were highly evaluated.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.112-118
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• 2023

As technology advances, the need for enhanced preparedness against cyber-attacks becomes an increasingly critical problem. Therefore, it is imperative to consider various circumstances and to prepare for cyber-attack strategic technology. This paper proposes a method to solve network security problems by applying reinforcement learning to cyber-security. In general, traditional static cyber-security methods have difficulty effectively responding to modern dynamic attack patterns. To address this, we implement cyber-attack scenarios such as 'Tiny Alpha' and 'Small Alpha' and evaluate the performance of various reinforcement learning methods using Network Attack Simulator, which is a cyber-attack simulation environment based on the gymnasium (formerly Open AI gym) interface. In addition, we experimented with different RL algorithms such as value-based methods (Q-Learning, Deep-Q-Network, and Double Deep-Q-Network) and policy-based methods (Actor-Critic). As a result, we observed that value-based methods with discrete action spaces consistently outperformed policy-based methods with continuous action spaces, demonstrating a performance difference ranging from a minimum of 20.9% to a maximum of 53.2%. This result shows that the scheme not only suggests opportunities for enhancing cybersecurity strategies, but also indicates potential applications in cyber-security education and system validation across a large number of domains such as military, government, and corporate sectors.

• 한국항행학회논문지
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• 제28권1호
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• pp.60-67
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• 2024

민간항공사고의 대부분은 인적요인에 의해 발생하고 특히 회전익 항공기는 예상하지 못하거나 의도하지 않게 악기상으로 진입하는 IIMC (instrument meteorological conditions) 상황에서의 사고가 많이 발생하고 있다. 이 연구는 저시정 조건에서 회전익 항공기 조종사의 에러율를 다각적으로 분석하여 비행특성에 관한 통찰력을 얻고 IIMC 상황에서의 사고를 줄이기 위한 방안을 연구하였다. 저시정 조건에서 조종사의 에러 발생율을 모션이 장착된 비행 시뮬레이터를 활용하였으며 65명의 조종사가 실험에 참여하였다. 실험을 통해 획득한 비행 데이터로 비행시정 감소, 공간정위상실 유무, 조종사 자격 등 다양한 조건에 따라 에러 발생율을 비교 분석하였다. 분석결과 다양한 조건에서 비행특성에 대한 특이점을 발견할 수 있었고 조종사의 자격 등급, 계기비행 (IFR; instrument flight rules) 자격 유무, 비행단계별 에러 발생율에 유의미한 차이가 발생하였다. 이와 같은 연구의 결과는 조종사의 교육 및 훈련프로그램을 개선하고 IIMC 상황에서 항공기 사고예방에 중요한 기여를 할 것으로 기대된다.

• 한국전자통신학회논문지
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• 제19권3호
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• pp.619-624
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• 2024

스케일링 작업은 치과 잇몸치료 가운데 가장 기본적인 작업 중 하나로 치아에 붙어 굳은 치석을 제거하는 것이다. 그러나 미숙하고 전문적이지 못한 치석 제거로 잇몸에 손상을 입어 피가 다량 발생하거나, 치아에 타격을 줄 수도 있다. 이러한 이유로 스케일링의 경우 다양한 사람들의 잇몸 구조에 따라 섬세하게 작업해 주어야 하며, 충분한 실습이 이루어져야 한다. 대학의 관련 학과에서는 스케일링 실습을 진행하고 있다. 하지만, 충분한 실습을 해보지 못한 학생들의 관점에서 대상자를 선정하여 실습을 진행하는 일이 결코 쉬운 일이 아니며, 실습 대상자 역시 불편하고 불안하여 실습 참여를 피할 수 있다. 이에 본 연구에서는 가상현실을 이용해 실제 대상자가 아닌 가상의 환자를 제작하여 다양한 잇몸의 형태를 단계별로 구현하여 반복적인 실습과 다양한 스케일링 경험을 쌓을 수 있도록 가상현실 실습 시스템을 설계 및 구현하였다.

• 경영정보학연구
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• 제15권3호
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• pp.1-37
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• 2013

본 연구는 모바일 러닝의 활성화를 위한 서비스 융합의 가능성을 보고자 하였다. 이를 위해 모바일 러닝의 유형 및 특성을 분석 하였다. 먼저 현재 모바일 러닝 서비스는 어떤 서비스를 중심으로 활성화되고 있으며, 이러한 서비스를 중심으로 사용자의 활용도가 높은 서비스는 무엇인지 알아 보았다. 두 번째로는 모바일에서 주로 이뤄지고 있는 서비스와 이러닝에서 주로 이뤄지고 있는 서비스의 복합적 융합가능성을 살펴 보았다. 세 번째로는 모바일에서의 서비스와 이러닝에서의 공통된 서비스를 중심으로 앞으로 융합이 활성화 될 가능성을 살펴보았다. 분석을 위하여 포털 사이트에서 관련 웹페이지를 통하여 변수를 추출하였으며, 사회 네트워크 분석과 연관성 분석을 사용하였다. 이는 웹페이지마다 변수의 종류와 수가 다르기 때문에 전체적인 웹 상에서 각각의 변수들의 위치와 네트워크상에서의 복잡한 연결 정도를 살펴보기 힘들다. 이러한 문제점을 해결하기 위해 사회 네트워크 분석을 하였으며, 변수들 간의 연관규칙을 발견하고자 연관성 분석을 하였다. 규칙의 해석을 위해서는 사회 네트워크 분석 결과와 연관규칙을 함께 고려하여 살펴보았다. 분석 결과, 모바일에서 제공되는 서비스와 이러닝에서 제공되고 있는 공통된 서비스 중에서 빈도수가 높은 서비스로는 게임과 SNS로 나타났으며, 이외 결제, 광고, 메일, 이벤트, 동영상, 클라우드, 전자책, 증강현실, 취업 등으로 발견되었다. 이러한 서비스를 중심으로 이러닝의 다양한 서비스와 융합하여 이뤄지고 있음을 알 수 있었다. 공통된 서비스와 함께 모바일에서는 검색, 뉴스, GPS 등의 서비스가 활성화 되고 있으며, 이러닝에서는 시뮬레이션, 교양, 공교육 등의 서비스가 활성화 되고 있음을 알 수 있었다. 모바일과 이러닝의 공통된 변수를 기반으로 각각의 서비스의 융합이 높게 나타난 변수로는 모바일에서는 게임과 SNS, 게임과 스포츠, SNS와 광고, 게임과 이벤트, SNS와 전자책, 게임과 커뮤니티가 융합이 높게 나타났으며, 이러닝에서는 게임, 동영상, 상담, 전자책을 전항으로 하여 시뮬레이션, 말하기, 공교육, 출결관리 등의 서비스의 융합정도가 높게 나타난 것을 알 수 있었다. 다음으로 모바일서비스와 이러닝서비스의 공통된 서비스중에서, 모바일 러닝 서비스에서 활성화가 높은 서비스와 사용자를 기반한 모바일 러닝 서비스의 활성화가 높은 서비스인 게임, SNS, 전자책을 기준으로 서비스 융합 활성화 가능성을 예측했다. 본 연구결과를 통해 모바일을 활용한 이러닝 서비스의 관련 서비스 융합으로, 모바일 러닝의 활성화에 대한 전략적 방향성을 제안할 수 있을 것이다.

• 보건교육건강증진학회지
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• 제6권2호
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• pp.23-39
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• 1989

There have been a lot of considerable. discussion and debate surrounding the management model in the health insurance management system and opinions regarding the management operating cost. It is a well known fact that there have always been dissenting opinions and debates surrounding the issue. The management operating cost varies according to the scale of the management organization and component members characteristics of the insurance carrier. Therefore, it is necessary to examine and compare the management operating cost to the simulated management models developed to cover those eligible for the health insurance scheme in this country. Since the management operating cost can vary according to the different models of management, four alternative management models have been established based on the critical evaluation of existing theories concerned, as well as on the basis of the survey results and simulation attempts. The first alternative model is the Unique Insurance Carrier Model(Ⅰ) ; desigened to cover all of the people with no classification of insurance qualifications and finances from the source of contribution of the insured, nationwide. The second is the Management Model of Large-scale District Insurance Carrier(Ⅱ) ; this means the Korean society would be divided into 21 large districts; each having its own insurance carrier that would cover the people in that particular district with no classification of insurance qualifications arid finances as in Model I. The third is the Management Model of Insurance Carrier Divided by Area and Classified with Occupation if Largescale (Ⅲ) ; to serve the self-employed in the 21 districts divided as in Model Ⅱ. It would serve the employees and their dependents by separate insurance carriers in large-scale similar to the area of the district-scale for the self-employed, so that the insurance qualifications and finances would be classified with each of the insurance carriers: The last is the Management Model of the Multi - insurance Carrier (Ⅳ) based on the Si. Gun. Gu area which will cover their own self- employed people in the area with more than 150 additional insurance carriers covering the employees and their dependents. The manpower necessary to provide services to all of the people according to the four models is calculated through simulation trials. It indicates that the Management Model of Large-scale District Insurance Carrier requires the most manpower among the four alternative models. The unit management operating costs per the insured individuals and covered persons are leveled with several intervals based on the insurance recipients. in their characteristics. The interval levels derived from the regression analysis reveal that the larger the scale of the insurance carriers is in the number of those insured and covered. the more the unit management operating cost decreases. significantly. Moreover. the result of the quadratic functional formula also shows the U-shape significantly. The management operating costs derived from the simulated calculation. on the basis of the average salary and related cost per staff- member of the Health Insurance Societies for Occupational Labours and Korean Medical Insurance Corporation for the Official Servants and Private School Teachers in 1987 fiscal year. show that the Model of Multi-insurance Carrier warrants the highest management operating cost. Meanwhile the least expensive management operating cost is the Management Model of Unique Insurance Carrier. Insurance Carrier Divided by Area and Classified with Occupation in Large-scale. and Large-scale District Insurance Carrier. in order. Therefore. it is feasible to select the Unique Insurance Carrier Model among the four alternatives from the viewpoint of the management operating cost and in the sense of the flexibility in promoting the productivity of manpower in the human services field. However. the choice of the management model for health insurance systems and its application should be examined further utilizing the operation research analysis for such areas as the administrative efficiency and factors related to computer cost etc.