• 한국지형학회지
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• 제27권2호
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• pp.65-80
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• 2020

This paper deals with risk assessment of life in a landslide-prone area by a GIS-based modeling method. Landslide susceptibility maps can provide a probability of landslide prone areas to mitigate or proper control this problems and to take any development plan and disaster management. A landslide inventory map of the study area was prepared based on past historical information and aerial photography analysis. A total of 550 landslides have been counted at the whole study area. The extracted landslides were randomly selected and divided into two different groups, 50% of the landslides were used for model calibration and the other were used for validation purpose. Eleven causative factors (continuous and thematic) such as slope, aspect, curvature, topographic wetness index, elevation, forest type, forest crown density, geology, land-use, soil drainage, and soil texture were used in hazard analysis. The correlation between landslides and these factors, pixels were divided into several classes and frequency ratio was also extracted. Eventually, a landslide susceptibility map was constructed using a logistic regression model based on entire events. Moreover, the landslide susceptibility map was plotted with a receiver operating characteristic (ROC) curve and calculated the area under the curve (AUC) and tried to extract a success rate curve. Based on the results, logistic regression produced an 85.18% accuracy, so we believed that the model was reliable and acceptable for the landslide susceptibility analysis on the study area. In addition, for risk assessment, vulnerability scale were added for social thematic data layer. The study area predictive landslide affected pixels 2,000 and 5,000 were also calculated for making a probability table. In final calculation, the 2,000 predictive landslide affected pixels were assumed to run. The total population causalities were estimated as 7.75 person that was relatively close to the actual number published in Korean Annual Disaster Report, 2006.

• 에너지공학
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• 제2권1호
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• pp.45-53
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• 1993

연료전지의 R&D 평가에 있어 현재의 불확실한 상황하에서 미래의 의사결정에 유용한 결과를 제공할 수 있는 방법론을 고찰해 보았다. 시뮬레이션을 이용한 사례연구는 기초 입력자료가 동일하다는 가정하에 일정상의 선후관계만을 고려한 경우(Case 1), 동등 및 배제 하위프로젝트를 고려한 경우(Case 2) 및 각 단계의 병렬수행을 허용한 경우(Case 3)에 대하여 수행하였으며, 이를 통하여 병행된 연구의 단계별 성공확률은 서로 상관관계를 갖고 있으며 각 프로젝트의 성공확률은 Case 1, Case 2, Case 3 순으로 향상되었고 상업화 성공시기는 Case 3 에서 현저하게 단축됨을 확인할 수 있었다.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.303-313
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• 2020

This study investigates the factors affecting Industry 4.0 adoption in the curriculum of university students in Ho Chi Minh City, Vietnam. Universities need to respond to the changing faces of Industry 4.0 and, hence, Education 4.0. A mixed method including both qualitative and quantitative methodologies was utilized. An in-depth interview was carried out for exploring, reviewing, and testing content validity of constructs and measurement items. The pilot study was conducted with 120 respondents. The conceptual model and hypotheses were developed using data collected by a questionnaire survey distributed to 584 respondents by both electronic and paper forms with non-probability and convenience sampling techniques. The result of structural equation modeling showed that occupation relevance, skills, facility conditions, and social influence impacted on the intermediates variables, namely, relevance advantage, perceived usefulness, behavioral intention-to-use, and actual use. The independent variables are occupation relevance, skills, facility conditions, and social influence. They impact actual use through mediating constructs such as relevance advantage, perceived usefulness, and behavioral intention-to-use. The findings suggest that universities and students' efforts aimed at increasing the factors' perceptions of adoption of Industry 4.0 will contribute to implementation success, where success is defined as effectual usage of Industry 4.0.

• Archives of Plastic Surgery
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• 제48권3호
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• pp.287-292
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• 2021

Background We report the efficacy of a dual-plane approach using a Dufourmentel skin flap with a purse-string suture of the de-epithelized dermis to manage pseudoaneurysm at the vascular access site for hemodialysis. Methods A retrospective analysis was conducted of 61 patients from 2013 to 2018 with pseudoaneurysms at the arteriovenous fistula or graft who were treated with rhomboid excision, vessel repair with a purse-string suture, and a full-thickness Dufourmentel skin flap. The success rate was defined as the probability of complete wound closure and intact vascular access patency without infection or other complications. Results The success rate was 93.4% at 6 months postoperatively. Complications included newly occurring pseudoaneurysms (n=2), wound dehiscence (n=1) and bleeding (n=1). There were no complications such as stenosis or thrombosis from the procedure. Conclusions A dual-plane approach using a Dufourmentel skin flap with a purse-string suture for vessel repair was shown to be a favorable option for managing stable, small (diameter <2 cm) pseudoaneurysms without infection, rapid expansion, or patency issues of the vascular access.

• 한국군사과학기술학회지
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• 제25권4호
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• pp.412-424
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• 2022

Since traditional derivative-based optimization for noisy simulation shows bad performance, evolutionary algorithms are considered as substitutes. Especially in case when outputs are binary, more simulation trials are needed to get near-optimal solution since the outputs are discrete and have high and heterogeneous variance. In this paper, we propose a genetic algorithm called SARAGA which adopts dynamic resampling and fitness approximation using surrogate. SARAGA reduces unnecessary numbers of expensive simulations to estimate success probabilities estimated from binary simulation outputs. SARAGA allocates number of samples to each solution dynamically and sometimes approximates the fitness without additional expensive experiments. Experimental results show that this novel approach is effective and proper hyper parameter choice of surrogate and resampling can improve the performance of algorithm.

• 한국통신학회논문지
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• 제29권5B호
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• pp.508-519
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• 2004

이 논문에서는 MPLS를 사용한 인터넷 트래픽 엔지니어링에 사용될 수 있는 다중경로 한계조건 기반 라우팅 알고리즘을 제안한다. 기존에 사용되던 한계조건 기반 최단경로 라우팅 알고리즘은 트래픽 엔지니어링의 중요한 요소 중에 하나인 대역폭 한계조건이 큰 간을 가지는 경우에는 조건을 만족하는 경로를 찾지 못할 확률이 높아진다. 제안된 다중경로 알고리즘은 대역폭 한계조건을 만족하는 하나의 경로를 찾을 수 없는 경우, 대역폭 조건을 여러 개의 작은 값으로 나누어 각각의 작은 대역폭 한계조건에 대해 다중경로를 찾는 알고리즘이다. 시뮬레이션을 통하여 제안한 알고리즘을 사용할 경우 주어진 네트웍 상황과 대역폭 한계 조건에서 더 높은 경로설정 성공확률을 나타내며, 네트웍 자원 이용률도 개선되는 것을 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3377-3395
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• 2015

Recently, several approaches to share road conditions and/or digital contents through VANETs have been proposed, and such approaches have generally considered the radial distance from the information source as well as the TTL to provision an ephemeral, geographically-limited information sharing service. However, they implement general MANETs and have not been tailored to the constrained movement of vehicles on roads that are mostly linear. In this paper, we propose a novel application-level mechanism that can be used to share road conditions, including accidents, detours and congestion, through a VANET. We assign probabilities to roads around each of the intersections in the neighborhood road network. We then use the graph representation of the road network to build a spanning tree of roads with the information source as the root node. Nodes below the root represent junctions, and the edges represent inter-connecting road segments. Messages propagate along the branches of the tree, and as the information propagates down the branches, the probability of replication decreases. The information is replicated until a threshold probability has been reached, and our method also ensures that messages are not delivered to irrelevant vehicles, independently of their proximity to the source. We evaluated the success rate and performance of this approach using NS-3 simulations, and we used IDM car following and MOBIL lane change models to provide realistic modeling of the vehicle mobility.

• 인터넷정보학회논문지
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• 제5권2호
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• pp.49-55
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• 2004

전자 우편을 이용함에 있어서 수신자의 전자 우편 주소 입력 시 오타 혹은 오기로 인해 발생할 수 있는 전자 우편 발송의 실패에 대해 수신자 실명을 표시하는 전자 우편 시스템 개발을 위한 방법을 연구하였다. 수신자 실명을 표시하는 전자 우편 시스템이란 전자 우편 자성 시 발송자가 입력하는 수신자의 전자 우편 주소를 통해 수신자의 실명을 데이터베이스를 통해 검색한 후 검색된 실명을 발송자에게 보여줌으로써 전자 우편의 발송확률을 높이는 시스템이다. 본 연구는 전자 우편의 발송 성공률과 데이터의 유출, 부정확한 전자 우편 발송에 따른 서버의 과부하와 이로 인한 경제적 손실을 최소화하는데 그 목적이 있다.

• 한국정보통신학회논문지
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• 제12권2호
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• pp.360-368
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• 2008

본 논문에서는 다중 서비스 다중 사용자 OFDMA 시스템의 임의 접근채널에서 차별화된 서 비스 품질을 제공하기 위하여 backoff기반 임의 접근 알고리즘을 제안하고, 임의 접근 채널의 주 자원인 부채널의 수와 PN-코드의 수가 주어진 경우, 제안된 알고리즘의 성능을 각 서비스 클래스 접속 확률의 함수로서, 각 서비스 클래스의 접속 성공 확률, 처리율, 블로킹 확률, 접속 지연관점에서 분석한다. 수치적 분석을 통하여 제안된 backoff 기반 임의 접근 알고리즘이 서로 다른 서비스 클래스의 임의접근 시도들에게 차등한 서비스 품질을 제공할 수 있음을 보였다.

• 한국게임학회 논문지
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• 제19권3호
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• pp.25-32
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• 2019

본 논문은 유전 알고리즘을 통한 Match-3 게임의 레벨 자동 생성 방법을 제안한다. 적절한 난이도의 게임 레벨을 만들기 위하여 사람이 일일이 게임 레벨을 조절해야 한다면, 사람은 그것을 위한 많은 시간과 노력이 필요하다. 본 논문에서는 유전 알고리즘을 적용하여 Match-3 게임에서의 난이도에 맞는 블록조합을 생성한다. 각 게임 레벨의 블록조합이 진화되는 개체이다. 유전자인 정수로부터 블록조합 개체를 생성하고, 주어진 성공확률과 컴퓨터가 플레이했을 때의 성공확률이 가까워질수록 적합도가 높아지도록 설정하여 해당 블록조합을 진화시킨다. 이를 통해 게임 난이도에 맞는 적절한 블록조합들을 생성하는 데 성공하였으며, 실험한 결과 컴퓨터가 결정한 난이도가 실제 사람이 게임했을 때의 결과에 영향을 준다는 것을 확인하였다.