• 한국항해항만학회지
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• 제46권5호
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• pp.458-470
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• 2022

As the 4th industrial revolution progresses, the application of several cutting-edge technologies such as the Internet of Things, big data, and mixed reality (MR) in relation to autonomous ships is being considered in the maritime logistics field. The aim of this study was to apply the concept of a digital twin model based on Human Machine Interaction (HMI) including a digital twin model and the role of an operator to a ship. The role of the digital twin is divided into information provision, support, decision, and implementation. The role of the operator is divided into operation, decision-making, supervision, and standby. The system constituting the ship was investigated. The digital twin system that could be applied to the ship was also investigated. The cloud-based digital twin system architecture that could apply investigated applications was divided into ship data collection (part 1), cloud system (part 2), analysis system/ application (part 3), and MR/mobile system (part 4). A Mixed Reality device HoloLens was used as an HMI equipment to perform a simulation test of a digital twin system of an 8 m battery-based electric propulsion ship.

• 한국BIM학회 논문집
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• 제8권4호
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• pp.34-40
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• 2018

As the number of aged bridges increases, the development of efficient bridge maintenance techniques is becoming more important. Particularly, there have been many studies on digital-twin models of bridges for maintenance and SHM (Structure Health Monitering). However, in order to use the digital-twin model for maintenance of the bridge, the model updating process that matches the structural response between the real bridge and the digital-twin bridge model must be done. This study presents a model updating method that adjusts bridge's stiffness and boundary condition with genetic algorithm (GA) using static displacements and verified proposed updating method through field test on PSC girder bridge. This study also proposes a conceptual idea to construct an efficient bridge maintenance system by applying the updated numerical analysis model to the digital-twin model.

• 지적과 국토정보
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• 제53권1호
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• pp.123-137
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• 2023

본 연구는 디지털트윈에 관한 국내·외 주요 동향을 조사·분석하여 우리나라의 디지털트윈 발전을 위한 시사점 도출을 목적으로 한다. 디지털트윈은 그 목적에 따라 상이한 정의들이 존재하나, 공통적으로는 시각화, 모니터링, 분석/예측/최적화와 관련한 기술적 사항들을 강조하고 있다. 이러한 디지털트윈의 주요 개념을 기준으로 하여 국내·외 도시 분야에 해당하는 디지털트윈 동향들을 분석하였으며, 해당 결과를 토대로 향후 우리나라 디지털트윈의 발전을 위한 데이터 관점에서의 시사점을 제시하였다.

• 한국시뮬레이션학회논문지
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• 제29권2호
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• pp.11-20
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• 2020

제조환경이 더욱 복잡해짐에 따라 전통적인 시뮬레이션만으로는 실시간 현장 결과를 평가하는 데 많은 어려움을 겪고 있다. 이를 극복하기 위한 대안으로 Digital Twin개념이 활발히 논의되고 있지만, 제품설계 단계에 국한되어 연구가 진행되고 있는 실정이다. 본 연구는 Digital Twin개념이 생산 공정 프로세스에 적용되기 위한 Digital Twin 기반 제조환경 프레임워크를 제시하였다. 구성요소는 실제 생산환경인 물리적 시스템과 데이터베이스, 그리고 가상 시스템인 트윈 모델을 제안하였다. 본 연구에서는 Arena 소프트웨어와 엑셀 VBA를 활용하여 컨베이어 시스템을 대상으로 간단한 Digital Twin 기반 제조시스템을 모의실험하였다. 실험결과 트윈 모델이 실제 물리적 시스템의 실시간 데이터를 전송받아 동일한 시간단위로 작동됨을 확인하였고, 엑셀 VBA에서 축적된 실시간 데이터와 학습 데이터를 기반으로 조정된 파라미터를 생성하고 있음을 확인하였다. 또한, 간단한 모의실험을 통해 Digital Twin 모델 구동 방법을 제안하였으며, Digital Twin 모델의 구현 가능성을 보여주었다.

• 한국IT서비스학회지
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• 제18권3호
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• pp.75-93
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• 2019

Digital twin technology is one of the key technologies to strengthen the competitiveness of manufacturing industry from the viewpoint of digital transformation in the era of $4^{th}$ industrial revolution. In this research, the important role in using digital twin technology in product design, This paper summarizes and empirically verifies the technical characteristics of digital twins, a key concept in the digital transition of the manufacturing industry. In this study, the technology characteristics of digital twin which is key concept in the digital transformation of manufacturing industry are summarized and empirically validated which factors militate a critical role in the use of digital twin technology in product design which is key area of product development. As a result of analysis, datafication, intellectualization which are characteristics of digital twin technology and task characteristics of product design influence Task Technology Fit (TTF) and Task Technology Fit (TTF) influences Technology (UTAUT) And finally, performance expectancy, effort expectancy, social influence and facilitating conditions affect usage intention.

• 한국BIM학회 논문집
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• 제9권3호
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• pp.1-7
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• 2019

Digital twin technology has been actively developed to monitor and assess the current state of actual structures. The digital twin changes the traditional observation method performed in the field to the real-time observation and detection system using virtual online model. Thus, this study designed a digital twin model for a beam and examined the feasibility of the digital twin for bridges. To reflect the current state of the bridge, model updating was performed according to the field test data to construct an analysis model. Based on the constructed bridge analysis model, the relationship between strain and displacement was used to represent a virtual model that behaves in the same way as the actual structure. The strain and displacement relationship was expressed as a matrix derived using an approximate analytical theory. Then, displacements can be obtained using the measured data obtained from strain sensors installed on the bridge. The coordinates of the obtained displacements are used to construct a virtual digital model for the bridge. For verification, a beam was fabricated and tested to evaluate the digital twin model constructed in this study. The displacements obtained from the strain and displacement relationship agrees well with the actual displacements of the beam. In addition, the displacements obtained from the virtual model was visualized at the locations of the strain sensor.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.305-307
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• 2021

본 논문에서는 ICT(Information Communication Technology) 기술을 이용하여 스마트팩토리 기반 CPPS(Cyber Pysical Production System)를 활용한 Digital-Twin 플랫폼 개발과 관련된 연구를 제안한다. 본 연구를 통해 개발된 플랫폼은 선행 제조 공정 계획 단계부터 BOP(Bill of Process) 관리 기능을 포함하여 P3R(Product, Process, Plant, Resource)을 연계한 3D Model 시뮬레이션 기능을 수행한다. 또한 생산 공정, 설비, 레이아웃, 생산량 예측이 가능한 Digital Twin 플랫폼을 제안한다. 본 논문을 통해 제안된 플랫폼은 초기 계획 설계 단계에서부터 제조, 생산, 운영 및 유지보수 단계까지의 전체 스마트팩토리 제조 공정을 관리할 수 있는 특징을 제안하였다.

• 한국인공지능학회지
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• 제9권2호
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• pp.7-14
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• 2021

Purpose: To solve urban problems, empirical research is being actively conducted to implement a smart city based on various ICT technologies, and digital twin technology is needed to effectively implement a smart city. A digital twin is essential for the realization of a smart city. A digital twin is a virtual environment that intuitively visualizes multidimensional data in the real world based on 3D. Digital twin is implemented on the premise of the convergence of GIS and BIM, and in particular, a lot of time is invested in data pre-processing and labeling in the data construction process. In digital twin, data quality is prioritized for consistency with reality, but there is a limit to data inspection with the naked eye. Therefore, in order to improve the required time and quality of digital twin construction, it was attempted to detect a building using Mask R-CNN, a deep learning-based masking algorithm for aerial images. If the results of this study are advanced and used to build digital twin data, it is thought that a high-quality smart city can be realized.

• 한국임상수의학회지
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• 제29권1호
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• pp.33-37
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• 2012

This study was performed to evaluate the rate of twin pregnancy and parturition in dairy cows. Calving records of Holstein dairy cows from 1998 to 2009 comprising Goyang and Paju cities herd with 20,990 calving events representing 820 twin births were used to evaluate twinning rate, calf sex ratio, periods of pregnancy and complication after parturition in single and twin births. Overall, the reported twinning rate was 3.9% in Holstein dairy cows. Rate of bicornual pregnancy (75%) was larger than that of unicornual pregnancy (25%) among cows having twin. Regardless of parity, the greatest twinning rate was observed in fall season from September to November. Calf sex ratios (male, M; female, F) were 48.0% FM, 28.9% MM, 21.5% FF and 0.9% mummifications for twin calves. Parturition type among cows having twins included normal (4.7%), premature (66.9%), delayed (9.2%), abortion (18.4%) and mummification (0.8%). The period of pregnancy in twin pregnancy (mean 272.6 days) was shorter than single pregnancy (mean 278.1 days). The retained placenta after parturition was over fourth times such as twin parturition (34.8%) higher than single parturition (8.5%) and the abomasal displacement was over two times such as twin parturition (10.2%) higher than single parturition (4.9%). The distribution of twin pregnancy with parities was high rate during the 2~3 parities. The prevalence of complication such as retained placenta and abomasal displacement with twin parturition revealed higher than single parturition.

• 한국항해학회지
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• 제21권1호
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• pp.103-108
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• 1997

Mathematical model of maneuvering motion for a single-screw single-rudder ship is established and several applications to the special situations of maneuvering are attempted. While, the mathematical model for twin-screw twin-rudder ship is not presented so much, because that type of ship is not popular. Lee et al. have examined the characteristics of such ship by captive model tests in 1988, in Japan. This paper proposes new mathematical models for propeller effective wake (1 -${\omega}_p$) and effective neutral rudder angle ${delta}_R$ in the case of twin-screw twin-rudder ship. And some maneuvering motionse are calculated with proposed models and compared with exact simulations.