• 한국BIM학회 논문집
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• 제9권2호
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• pp.11-20
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• 2019

The use of drones and laser scanners have the potential to drastically reduce the time and costs of conventional techniques employed for field survey of cultural heritage buildings. Moreover, point cloud data can be utilized to create an as-built Building Information Model (BIM), providing a repository for consistent operations information. However, BIM creation is not a requisite for heritage buildings, and their technological possibilities and barriers have not been documented. This research explored the processes required to convert a heritage university building to a BIM model, using existing off-the-shelf software applications. Point cloud data was gathered from drones for the exterior, while a laser scanner was employed for the interior of the building. The point clouds were preprocessed and used as references for the geometry of the building elements, including walls, slabs, windows, doors, and staircases. The BIM model was subsequently created for the individual elements using existing and custom libraries. The model was used to extract 2D CAD drawings that met the requirements of Korea's heritage preservation specifications. The experiment showed that technical improvements were needed to overcome issues of occlusion, modeling errors due to modeler's subjective judgements and point cloud data cleaning and filtering techniques.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.478-492
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• 2021

In this study, hull dimensions of an FPSO were optimized to maximize its operability at Brazil field. In contrast with the previous works which have used simplified models to evaluate some indicators related to stability and hydrodynamic performances of FPSOs for its own optimal design, we developed a generic hull and compartment modeler and sophisticated stability and hydrodynamic calculation modules. With the aid of the developed tools, the hull optimization was performed with initial dimensions of an FPSO originally designed for west Africa field. The optimization results indicated the relative importance of hydrodynamic performances compared with stability performances for the FPSO hull dimensioning by showing that there were 3 active constraints related to them, which were the natural periods of heave and roll and the maximum pitch angle under 1-year return period waves at full load condition. To the author's knowledge, this study is the first attempt to combine altogether the hull and compartment modeling and full set of stability and hydrodynamic calculations precisely to optimize an FPSO's hull dimensions within 30 min. Also, it is worthwhile to mention that the developed methods are generic enough to be applied to all types of ship-shaped offshore platforms.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1063-1069
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• 2022

In modern industry, vacuum has grown into an indispensable industrial field. The performance of the vacuum pump in the degasser system among mud treatment system facilities was verified by a numerical analysis method. The degasser system is an equipment for removing the gas contained in the mud, and it is a work process that requires a vacuum. This study analyzed the vacuum pump performance of the degasser used in drilling for resource development of onshore and offshore plants. The vacuum pump used in the degasser system was designed with a discharge rate of 0.099kg/s. The DM(Design Modeler) program of ansys workbench 17.2 was used to modify the model of the vacuum pump used in the degasser system. And for performance analysis, CFX, which is known to be suitable for rotating system analysis, was used. Finally the performance analysis results of the vacuum pump and the prototype performance test results were compared and analyzed.

• ETRI Journal
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• 제44권1호
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• pp.135-146
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• 2022

The importance of big data analytics has become apparent with the increasing volume of data on the Internet. The amount of data will increase even more with the widespread use of Internet of Things (IoT). One of the most important application areas of the IoT is healthcare. This study introduces new real-time data analytics architecture for an IoT-based smart healthcare system, which consists of a wireless sensor network and a radio-frequency identification technology in a vertical domain. The proposed platform also includes high-performance data analytics tools, such as Kafka, Spark, MongoDB, and NodeJS, in a horizontal domain. To investigate the performance of the system developed, a diagnosis of Wolff-Parkinson-White syndrome by logistic regression is discussed. The results show that the proposed IoT data analytics system can successfully process health data in real-time with an accuracy rate of 95% and it can handle large volumes of data. The developed system also communicates with a riverbed modeler using Transmission Control Protocol (TCP) to model any IoT-enabling technology. Therefore, the proposed architecture can be used as a time-saving experimental environment for any IoT-based system.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.176-181
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• 2011

A role of cost modeler is that of facilitating design process by the systematic application of cost factors so as to maintain sensible and economic relationships between cost, quantity, utility and appearance. These relationships help to achieve the client's requirements within an agreed budget. The purpose of this study is to develop a parametric cost estimating model for the early design stage by using the multi-dimensional system of OLAP (On-line Analytical Processing) based on the case of quantity data related to architectural design features. The parametric cost estimating models have been adopted to support decision making in the early design stage. These models typically use a similar instance or a pattern of historical case. In order to effectively use this type of data model, it is required to set data classification and prediction methods. One of the methods is to find the similar class in line with attribute selection measure in the multi-dimensional data model. Therefore, this research is to analyze the relevance attribute influenced by architectural design features with the subject of case-based quantity data used for the parametric cost estimating model. The relevance attributes can be analyzed by Analytical Characterization. It helps determine what attributes to be included in the OLAP multi-dimension.

• Asia pacific journal of information systems
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• 제28권2호
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• pp.75-92
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• 2018

Conceptual modeling is well suited as a subject that constitutes the "core" of the Information Systems (IS) discipline and has grown in response to IS development. Several modeling grammars and methods have been studied extensively in the IS discipline. Previous studies, however, present deficiencies in research methods and even put forward contradictory results about the ternary relationship in conceptual modeling. For instance, some studies contend that the semantics of a binary relationship are better for novices, but others argue that a ternary relationship is better than three binary relationships when the association among three entity types clearly exists. The objective of this research is to acquire complete and accurate understanding of the ternary relationship, specifically to understand practitioners' modeling performance when utilizing either a ternary or binary relationship. To the best of our knowledge, no previous work clearly compares real-world modeler performance differences between binary and ternary representations. By investigating practitioners' understanding of ternary relationship and identifying practitioners' cognition, this research can broaden the perspective on conceptual modeling.

• 지능정보연구
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• 제24권2호
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• pp.149-169
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• 2018

본 연구에서는 한국문화관광연구원에서 조사된 "2013년~2015년 외래 관광객 실태조사"의 약 36,000개 데이터에 대한 빅 데이터 분석을 통해 관광산업 활성화 방안을 도출해 보고자 한다. 이를 위해서 외래 관광객들의 '전반적 만족도', '재방문 의사', '추천의사' 변수에 가장 많은 영향을 끼치는 요인을 분석하고 해당 요인들의 각각에 대한 영향력에 대해 파악 하였다. 본 연구에서는 SPSS IBM Modeler 16.0의 의사결정나무(C5.0, CART, CHAID, QUEST), 인공신경망, 로지스틱 회귀분석의 데이터마이닝 기법을 이용하여 종속변수에 가장 큰 영향을 미치는 상위 변수 7개씩을 각각 도출하였고, 추가적으로 각 독립변수들의 영향력을 심도 있게 파악하기 위하여 R프로그래밍을 활용하여 SPSS IBM Modeler 16.0을 통해 도출된 각 독립변수들의 영향력을 파악하였다. 데이터 분석 결과 '전반적 만족도'에 가장 영향을 미치는 상위 변수 7개는 관광지매력도, 음식만족도, 숙박만족도, 교통수단만족도, 안내서비스만족도, 방문관광지수, 국가로 나타났으며 가장 큰 영향력을 미친 변수는 음식만족도와 관광지매력도로 분석되었다. '재방문 의사'에 가장 영향을 미치는 상위 변수 7개로는 국가, 여행 동기, 활동, 음식만족도, 제일 좋았던 활동, 관광안내서비스만족도, 관광지매력도로 나타났으며 그중 가장 큰 영향력을 미친 변수는 음식만족도와 여행 동기로 분석되었다. 마지막으로 '추천의사'에 영향을 미치는 상위 변수 7개로는 국가, 관광지매력도, 방문관광지수, 음식만족도, 활동, 관광안내서비스만족도, 비용으로 나타났으며 가장 큰 영향력을 미친 변수는 국가, 관광지매력도, 음식만족도로 분석되었다. 따라서 세 변수에 공통적으로 영향을 끼치는 요인은 음식만족도, 관광지매력도로 분석되었으며 해당 요인들이 공통적으로 한국여행에 대한 전반적 만족도와 재방문 의사, 추천의사에 미치는 영향이 크다는 것을 확인할 수 있었다. 본 연구는 외래 관광객들의 한국관광에 대한 활성화 방안을 "외래 관광객 실태조사" 빅 데이터 분석을 통해 규명함으로써 한국 관광 데이터 분석의 활용과 관광 정책 수립의 기초자료로 활용될 수 있을 것으로 기대되며 향후 기업 및 국가차원에서 한국 관광발전에 기여할 수 있는 활성화 방안을 마련하는 자료로 사용될 수 있을 것으로 기대한다.

• 전자공학회논문지SC
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• 제45권2호
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• pp.45-54
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• 2008

본 논문에서는 근거리 저속 무선 기술인 IEEE 802.15.4 이용한 무선 제어 시스템의 구현을 위해 동적 스케줄링 및 전송 기법을 제안하였다. 제안된 스케줄링 기법은 공장 환경에서 주어진 시간 구간 내에 실시간 혼합 데이터(실시간 주기 데이터, 긴급 데이터, 비실시간 메시지 데이터)를 효율적으로 처리하는 기능을 제공한다. 이를 위하여 IEEE 802.15.4의 슈퍼프레임의 구조적 특징을 응용하여 실시간 혼합 데이터의 효율적인 전송을 위한 동적 스케줄링 기법을 설계했다. 제안된 기법은 실시간 및 비실시간 데이터간에 독립적인 처리 알고리즘을 적용하기 때문에 전체적인 제어 네트워크의 성능 향상을 가져올 수 있다. 제안된 알고리즘의 효용성을 증명하기 위하여 OPnet Modeler 기반의 IEEE 802.15.4 시뮬레이션 모델을 구현하고 주어진 주기 및 긴급 데이터를 이용하여 제안된 기법이 실시간성 향상에 기여함을 보였다.

• 한국통신학회논문지
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• 제38B권2호
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• pp.130-139
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• 2013

최근 풍력 발전 단지가 대형화 해상화됨에 따라 이를 모니터링하고 제어하기 위한 통신망의 중요성이 높아지고 있다. 본 논문에서는 해상 풍력 단지에서 사용하는 기존 Ethernet 기반의 통신망의 문제점인 지연시간, 데이터 처리 오버헤드 및 풍력 발전기간 데이터 전송의 공평성 문제를 해결하기 위하여 EPON(Ethernet Passive Optical Network) 기반의 통신망 구조를 제안하고 성능 평가를 수행한다. 제안한 구조는 OLT(Optical Line Terminal)를 중앙 제어 센터에 설치하고 해상의 풍력 발전기에 ONU(Optical Network Unit)를 설치하여 점 대 다점 통신망을 구성하는 토폴로지이다. EPON 기반 토폴로지는 수동소자를 사용함으로써 망 구성 비용이 저렴하고 관리가 용이하며 높은 신뢰성과 데이터 전송의 공평성을 보장할 수 있다. 제안한 통신망 구조의 성능을 평가하기 위하여 OPNET Modeler를 이용하여 IEC 61850 표준을 기반으로 한 풍력단지를 모델링한다. 시뮬레이션 결과는 기존 이더넷 기반의 통신망과 지연시간, 오버헤드 및 전송의 공평성 관점에서 비교 분석한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.216-221
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• 2008

Shape design optimization for linear elasticity problem is performed using isogeometric analysis method. In many design optimization problems for real engineering models, initial raw data usually comes from CAD modeler. Then designer should convert this CAD data into finite element mesh data because conventional design optimization tools are generally based on finite element analysis. During this conversion there is some numerical error due to a geometry approximation, which causes accuracy problems in not only response analysis but also design sensitivity analysis. As a remedy of this phenomenon, the isogeometric analysis method is one of the promising approaches of shape design optimization. The main idea of isogeometric analysis is that the basis functions used in analysis is exactly same as ones which represent the geometry, and this geometrically exact model can be used shape sensitivity analysis and design optimization as well. In shape design sensitivity point of view, precise shape sensitivity is very essential for gradient-based optimization. In conventional finite element based optimization, higher order information such as normal vector and curvature term is inaccurate or even missing due to the use of linear interpolation functions. On the other hands, B-spline basis functions have sufficient continuity and their derivatives are smooth enough. Therefore normal vector and curvature terms can be exactly evaluated, which eventually yields precise optimal shapes. In this article, isogeometric analysis method is utilized for the shape design optimization. By virtue of B-spline basis function, an exact geometry can be handled without finite element meshes. Moreover, initial CAD data are used throughout the optimization process, including response analysis, shape sensitivity analysis, design parameterization and shape optimization, without subsequent communication with CAD description.