• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.101-107
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• 2019

This study conducted a simulation to observe the performance of a multi-turbocharged gasoline internal combustion engine for a high-altitude long-endurance unmanned aerial vehicle (HALE UAV). The WAVE 1-D engine simulation software from Ricardo was used for the engine system modeling and simulation. The specifications of a 2.4-L four cylinder gasoline engine from commercial vehicles and maps of commercial vehicle turbochargers were applied to the multi-stage turbocharged engine system model. Three turbochargers and intercoolers were installed in series for the appropriate intake of pressure for the gasoline engine at a high altitude of 60,000 ft. There was one wastegate for the turbochargers. The operability of the engine system was analyzed via this simulation model.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.91-101
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• 2016

PURPOSES : The aim of this study was to compare the performance of the QUEENSOD method and the gravity model in estimating Origin-Destination (O/D) tables for a large-sized microscopic traffic simulation network. METHODS : In this study, an expressway network was simulated using the microscopic traffic simulation model, VISSIM. The gravity model and QUEENSOD method were used to estimate the O/D pairs between internal and between external zones. RESULTS: After obtaining estimations of the O/D table by using both the gravity model and the QUEENSOD method, the value of the root mean square error (RMSE) for O/D pairs between internal zones were compared. For the gravity model and the QUEENSOD method, the RMSE obtained were 386.0 and 241.2, respectively. The O/D tables estimated using both methods were then entered into the VISSIM networks and calibrated with measured travel time. The resulting estimated travel times were then compared. For the gravity model and the QUEENSOD method, the estimated travel times showed 1.16% and 0.45% deviation from the surveyed travel time, respectively. CONCLUSIONS : In building a large-sized microscopic traffic simulation network, an O/D matrix is essential in order to produce reliable analysis results. When link counts from diverse ITS facilities are available, the QUEENSOD method outperforms the gravity model.

• Journal of Ocean Engineering and Technology
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• v.30 no.5
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• pp.367-373
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• 2016

This paper describes the development of a navigation HILS (hardware in the loop simulation) system for an integrated navigation performance analysis of a large diameter unmanned underwater vehicle (LDUUV). The HILS system was used for the performance analysis of the LDUUV. When a conventional HILS system is used, it is not possible to calculate the velocity and position using an inertial navigation system (INS). To cope with this problem, an external acceleration was generated. To evaluate the proposed method, we compare the results of a Monte Carlo simulation and navigation HILS experiment.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.309-315
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• 2007

This study was performed to develop a simulation model of circulating concurrent-flow rice dryer. The simulation model consists of drying model, tempering model and crack prediction model. The drying and tempering models were developed based on mathematical analysis, and the crack prediction model was developed by thin layer drying tests. Rice drying tests were done with three replications by use of a pilot scale dryer of holding capacity of 700 kg. Experimental values for moisture content, rice temperature, rice crack, and drying energy were compared with predicted values by simulation model. The RMSEs of predicted moisture contents were ranged from 0.5807% (d.b.) to 1.1951% (d.b.). and the coefficients of determination were 0.9688 to 0.9812. The RMSEs of predicted rice temperatures at the exit of the drying chamber were 1.83 to $3.81^{\circ}C$ and the coefficients of determination were 0.8834 to 0.9482. The results for moisture contents and rice temperatures showed very good relationships between predicted values and experimental values. The RMSEs of predicted value of crack ratio were 0.4082 to 0.7967% and the coefficients of determination were 0.8742 to 0.9547.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.1
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• pp.195-209
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• 2018

This study reviewed emerging trends in 3D technology adopted in apparel design research and product development for rapid prototyping and effective evaluation of product performance. Based on a literature review, the authors discussed technical advantages, practical merits and limitations, applications, and on-going developmental efforts of the following methodologies focusing on 3D body scanning and 3D motion capture, and 3D virtual fit simulation technologies. Such data-driven technical approaches observed in recent apparel design research and industry practice are expected to increasingly be adopted in the field to improve consumers' satisfaction with functionality, aesthetics, and comfort of a wide range of apparel products that include daily wear, sport apparel and protective clothing.

• Fashion & Textile Research Journal
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• v.16 no.6
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• pp.921-926
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• 2014

The aim of this study is to develop upper bodice pattern for obese girls aged 10~12 by using 3D virtual garment simulation system. The criteria for subjects in this study were girls who had over 1.46 of the R$\ddot{o}$hrer Index. A total of 229 schoolgirls who met these criteria were enrolled. The results of this study are as follows: First, by using 3D virtual garment simulation, new upper bodice pattern considered obese-schoolgirls was development. The basic numerical formula were as follows ; bust girth B/2+4.5, armhole depth B/4-1, waist girth W/4+0.5+dart amount, front chest width B/6+2, back width B/6+2, neck width B/12-0.5 and neck depth B/12+0.5. Second, armhole darts were added to compensate the loose amount of front armhole and dart manipulation was used to ensure a better appearance on armhole in the design. The dart side line was modified concavely to help cover the protruding stomach. Curved lines on the armhole were significantly relieved using dart manipulation and the darts side line was modified concavely to reduce the tightness around the front waist darts. Third, according to the results of the new upper bodice pattern's appearance evaluation, it estimated more highly than existing pattern in silhouette and ease amount, confirming that new upper bodice pattern was appropriate for the obese-schoolgirls. This study is expected to serve as one of important basic data for ensuing studies that may utilize 3D virtual garment simulation system with 2D patterns.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.6
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• pp.554-564
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• 2020

In environment of torpedo firing, underwater acoustic signal is generated by target and noise. Sound wave which is generated from acoustic signal is propagated by seawater and it is received through the sonar(sound navigation and ranging) system mounted on torpedo. In the ocean, acoustic signal or sound wave from target that is generated by the spread of broadband can be attenuated by ambient noise and can be lost by medium and environment. This research is designed to support teamwork training in Naval operations by constructing a simulation system that is more similar to the real-world conditions. This paper attempts to research the modeling of target detection and to develop the simulation of torpedo sonar(TOSO). In order to develop the realistic simulation, we researched the broadband sound modeling of target and noise source, the modeling of acoustic transmission loss by chemical component of seawater, and the modeling of signal attenuation by ambient noise environment which is approximated by experimental measurements in seawater surrounding the Korea Peninsular and by experience of Navy's actual torpedo firing. This research contributed to constructing more practical simulation of torpedo firing in real time and the results of this research were used to develop a teamwork training system for the Navy and their education.

• Journal of International Society for Simulation Surgery
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• v.1 no.1
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• pp.41-44
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• 2014

The aim of this report is showing the case that we could give exact navigation of perigastric vessels for gastrectomy with 3D CTA. A 74-year-old male patient visited hospital with gastric cancer. Early gastric cancer, type IIb was found at stomach antrum great curvature side. Before surgery, he underwent 3D CT angiography. 3D volume rendering images and MIP images were made by post processing. He had replaced Lt. hepatic artery arising from Lt. gastric artery. Surgeon could get patient's specific vascular anatomy before surgery including surgically relevant anatomical distance and direction and could finish gastrectomy within 4 hours and just 53ml blood loss.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.1555-1558
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• 2011

국방 모델링 및 시뮬레이션(Modeling & Simulation) 소프트웨어 분야에서 분산 시뮬레이션 기술표준인 HLA(High Level Architecture)의 적용이 늘어나고 있으며, 시뮬레이션 요소의 재사용성 및 신뢰성 확보를 위한 개발 프레임워크 제공이 핵심기술로 떠오르고 있다. 특히, 시뮬레이션을 위한 공통 서비스를 제공하는 M&S 프레임워크가 개발되었다. 또한, 가상의 시험 환경을 제공하기 위한 요소 중 시험환경의 구성을 위한 시나리오 모델이 있다. 본 논문에서는 시험 환경을 구성하기 위한 M&S 프레임워크 내의 시나리오의 스키마 설계에 대해서 기술한다.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.231-242
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• 2010

In order to assess applicability of debris flow simulation on natural terrain in Korea, this study introduced the DEBRIS-2D program which had been developed by Liu and Huang (2006). For simulation of large debris flows composed of fine and coarse materials, DEBRIS-2D was developed using the constitutive relation proposed by Julien and Lan (1991). Based on the theory of DEBRIS-2D, this study selected a valley where a large debris flow was occurred on July 16th, 2006 at Deoksanri, Inje county, Korea. The simulation results show that all mass were already flowed into the stream at 10 minutes after starting. In 10minutes, the debris flow reached the first geological turn and an open area, resulting in slow velocity and changing its flow direction. After that, debris flow started accelerating again and it reached the village after 40 minutes. The maximum velocity is rather low between 1 m/sec and 2 m/sec. This is the reason why debris flow took 50 minutes to reach the village. The depth change of debris flow shows enormous effect of the valley shape. The simulated result is very similar to what happened in the field. It means that DEBRIS-2D program can be applied to the geologic and topographic conditions in Korea without large modification of analysis algorithm. However, it is necessary to determine optimal reference values of Korean geologic and topographic properties for more reliable simulation of debris flows.