• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3393-3412
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• 2017

As a main challenge in network virtualization, virtual network embedding problem is increasingly important and heuristic algorithms are of great interest. Aiming at the problems of poor correlation in node embedding and link embedding, long distance between adjacent virtual nodes and imbalance resource consumption of network components during embedding, we herein propose a two-stage virtual network embedding algorithm NA-PVNM. In node embedding stage, resource requirement and breadth first search algorithm are introduced to sort virtual nodes, and a node fitness function is developed to find the best substrate node. In link embedding stage, a path fitness function is developed to find the best path in which available bandwidth, CPU and path length are considered. Simulation results showed that the proposed algorithm could shorten link embedding distance, increase the acceptance ratio and revenue to cost ratio compared to previously reported algorithms. We also analyzed the impact of position constraint and substrate network attribute on algorithm performance, as well as the utilization of the substrate network resources during embedding via simulation. The results showed that, under the constraint of substrate resource distribution and virtual network requests, the critical factor of improving success ratio is to reduce resource consumption during embedding.

• 드라이브 ㆍ 컨트롤
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• 제12권2호
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• pp.27-33
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• 2015

Excavators are versatile earthmoving equipment that are used in civil engineering, hydraulic engineering, grading and landscaping, pipeline construction and mining. Effective operator training is essential to ensure safe and efficient operating of the machine. The virtual reality excavator based on simulation using conventional large size monitors is limited by the inability to provide a realistic real world training experience. We proposed a flexible observation method with a head tracking system to improve user feeling and sensation when operating a virtual reality excavator. First, an excavation simulator is designed by combining an excavator SimMechanics model and the virtual world. Second, a head mounted display (HMD) device is presented to replace the cumbersome large screens. Moreover, an Inertial Measurement Unit (IMU) sensor is mounted to the HMD for tracking the movement of the operator's head. These signals consequently change the virtual viewpoint of the virtual reality excavator. Simulation results were used to analyze the performance of the proposed system.

• 복식문화연구
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• 제23권4호
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• pp.616-627
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• 2015

The purpose of this study was to develop slacks patterns for obese-schoolgirls aged 10~12 by using a 3D virtual garment simulation system. The criteria for subjects in this study were girls who had a BMI of over $25kg/m^2$. A total of 155 schoolgirls who met these criteria were enrolled. The results were as follows: First, by using 3D virtual garment simulation, a new slacks pattern considerate of obese-schoolgirls was developed. The basic numerical formulae were as follows: Front and back hip girth of H/4-0.5+1 and H/4+0.5+1.5, front waist girth of W/4+1+0.5, back waist girth of W/4+2+0.5, front crotch extension of H/16-0.5, back crotch extension of H/8-0.5, front dart amount of 1, and back dart amount of 2. Second, according to the new slacks pattern appearance evaluation, the new slacks pattern scored more highly than the existing pattern for silhouette and ease amount, confirming that the new slacks pattern is appropriate for obese-schoolgirls. Additionally, the new slacks pattern was evaluated allowing for the proper space length of the waist, abdomen and hips. This study is expected to serve as important basic data for ensuing studies that may utilize a 3D virtual garment simulation system with 2D patterns and for future 3D pattern production program development.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.13.1-13.12
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• 2016

Background: Mandibular motion tracking system (ManMoS) has been developed for orthognathic surgery. This article aimed to introduce the ManMoS and to examine the accuracy of this system. Methods: Skeletal and dental models are reconstructed in a virtual space from the DICOM data of three-dimensional computed tomography (3D-CT) recording and the STL data of 3D scanning, respectively. The ManMoS uniquely integrates the virtual dento-skeletal model with the real motion of the dental cast mounted on the simulator, using the reference splint. Positional change of the dental cast is tracked by using the 3D motion tracking equipment and reflects on the jaw position of the virtual model in real time, generating the mixed-reality surgical simulation. ManMoS was applied for two clinical cases having a facial asymmetry. In order to assess the accuracy of the ManMoS, the positional change of the lower dental arch was compared between the virtual and real models. Results: With the measurement data of the real lower dental cast as a reference, measurement error for the whole simulation system was less than 0.32 mm. In ManMoS, the skeletal and dental asymmetries were adequately diagnosed in three dimensions. Jaw repositioning was simulated with priority given to the skeletal correction rather than the occlusal correction. In two cases, facial asymmetry was successfully improved while a normal occlusal relationship was reconstructed. Positional change measured in the virtual model did not differ significantly from that in the real model. Conclusions: It was suggested that the accuracy of the ManMoS was good enough for a clinical use. This surgical simulation system appears to meet clinical demands well and is an important facilitator of communication between orthodontists and surgeons.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.854-861
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• 2005

The functional behavior of a portable consumer electronic (PCE) product is nearly all expressed with human-machine interaction (HMI) tasks. Although physical prototyping and computer aided design (CAD) software can show the appearance of the product, they cannot properly reflect its functional behavior. In this paper, we propose a virtual prototyping (VP) system that incorporates virtual reality and HMI functional simulation in order to enables users to capture not only the realistic look of a PCE product but also its functional behavior. We obtain geometric part models of the product and their assembly and kinematics information with the help of CAD and reverse engineering tools, and visualize them with various display tools. We adopt state transition methodology to capture the HMI functional behavior of the product into a state transition chart, which is later used to construct a finite state machine (FSM) for the functional simulation of the product. The FSM plays an important role to control the transition between states of the product. The proposed VP system receives input events such as mouse clicks on buttons and switches of the virtual prototype model, and it reacts to the events based on the FSM by activating associated activities. The VP system provides the realistic visualization of the product and the vivid simulation of its functional behavior. It can easily allow users to perform functional evaluation and usability testing. Moreover, it can greatly reduce communication errors occurring in a typical product development process. A case study about VP of an MP3 player is given to show the usefulness of the proposed VP system.

• 대한소아치과학회지
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• 제48권3호
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• pp.302-312
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• 2021

이 연구의 목적은 부정교합 모델을 적용한 프로토타입 가상현실(Virtual Reality, VR) 시뮬레이션을 개발하고, 치과 전공의와 치과대학생 간의 수행 결과 및 만족도 설문 비교를 통해 VR 시뮬레이션의 치의학 교육에의 응용 가능성을 평가하는 것이다. 참가자들은 가상 부정교합 모델을 관찰한 후 부정교합의 유형을 진단하고, 가상 부정교합 모델에 나타나는 임상 소견과 적절한 치료계획을 결정하는 세 가지 과제를 수행하였고, 총 5문항으로 구성된 만족도에 관한 설문을 작성하였다. 전공의 집단의 부정교합 평가에 관한 수행능력은 학생 집단과 비교해 유의하게 높았으며(p < 0.01), 두 집단 모두에서 첫 번째 증례를 수행하는 시간보다 두 번째 증례를 수행하는 시간이 유의하게 감소하였다(p < 0.01). 만족도 설문에서는 모든 문항에 대해 보통 이상의 긍정적인 반응을 보였다. 추후 VR 시뮬레이션의 지속적인 개발이 이루어진다면 가치 있는 교육 도구로 응용될 수 있을 것이다.

• 한국시뮬레이션학회논문지
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• 제28권2호
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• pp.169-177
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• 2019

전장상황의 변화와 첨단정보통신기술의 발전에 따라 과학화된 훈련체계인 LVC 훈련체계가 주목을 받고 있다. 대한민국 공군은 전투기 시뮬레이터를 중심으로 공중전투기동장비(ACMI), 워게임모델을 가상의 합성전장환경에 구현하여 실전적이고 과학적인 훈련이 가능한 LVC 훈련체계를 구축하고자 한다. 본 논문에서는 공군의 Virtual 체계인 전투기 시뮬레이터와 Constructive 체계인 전구급 연습용 모델의 V-C 연동시험 수행결과에 대해 다루고자 한다. 기종별로 각각 상이한 연동방식을 갖춘 F-15K, KF-16, FA-50 전투기 시뮬레이터를 표준 연동방식으로 변환하였으며, 합성 전장환경 모의 도구를 활용하여 3개 기종의 전투기 시뮬레이터가 상호 연동이 가능한 환경을 구축하였다. 그리고 공군의 연습용 모델인 창공모델도 표준 연동방식으로 변환하였으며, 연동 최적화를 위해 SW 일부를 수정하였다. 이를 통해 공군의 전투기 시뮬레이터와 워게임 모델이 연동이 가능함을 확인할 수 있었다. 본 연구결과는 향후 공군 LVC 훈련체계 개념연구 및 체계개발 간에 유의미하게 참조할 만한 근거가 될 것임을 기대한다.

• 한국콘텐츠학회논문지
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• 제19권2호
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• pp.661-670
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• 2019

본 연구는 가상현실 기술을 간호교육에 활용한 연구에 대해 알아보기 위해 시행된 체계적 문헌고찰이다. 연구대상 논문은 2018년도 11월 까지 출간된 논문으로 전자 데이터베이스인 PubMed, Proquest (nursing and allied health), CINAHL, RISS를 활용한 문헌검색이 이루어졌다. 검색어로는 'nursing education', 'simulation', 'skill training', 'virtual reality', 'VR'을 사용하였다. 총 695개의 논문이 검색되었고, 최종 7편의 문헌이 포함되었다. 7편 중 5편은 비동등성 대조군 실험설계 연구였으며 2편은 단일군 설계 연구였다. 이중 2편은 수기술 교육에 가상현실 기술을 활용하였으며 5편은 시나리오를 활용한 가상현실 시뮬레이션 교육이었다. 측정된 결과 변수는 수기술 능력, 지식, 총 VR 활용 학습시간, 자기효능감, 의사소통 능력이었고, 대체로 긍정적인 결과가 확인되었으나 일부 연구에서는 통계적으로 유의미하지 않은 결과도 있었다. 본 연구 결과는 가상현실을 활용한 간호교육의 효과에 대한 근거를 제시하였으나 향후 체계적인 측정과정이 포함된 중재 연구가 추가적으로 필요하다. 또한 기존의 수기술 교육프로그램과 시뮬레이션 교육과의 체계적인 비교연구를 통해 비용 등의 효과에 대한 근거제시가 이루어져야 할 것이다.

• 한국응용과학기술학회지
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• 제39권2호
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• pp.182-192
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• 2022

본 연구는 가상 시뮬레이션기반 노인간호 실습교육 실시 후 간호대학생의 몰입경험과 학습역량이 학습만족도에 미치는 영향을 파악하기 위한 조사연구이다. 연구 대상자는 간호대학 학생 72명을 대상으로 하였고, 자료수집은 2021년 4월 2일부터 5월 7일까지 온라인 설문을 통해 수행하였다. 자료분석은 SPSS/WIN 24.0을 이용하여 기술통계, 상관관계 및 다중회귀분석을 사용하였다. 연구결과, 가상 시뮬레이션 교육 후 간호대학생의 학습만족도는 몰입경험(r=.656, p<.001), 학습역량(r=.672, p<.001)과 유의한 정적 상관관계를 보였다. 학습만족도에 가장 영향력이 있는 요인은 학습역량(𝛽=.459, p<.001), 몰입경험(𝛽=.413, p<.001)으로 나타났으며 모형의 설명력은 60.9%이었다. 그러므로 가상 시뮬레이션 교육 후 학습만족도를 향상시키기 위해서 실습에 대한 몰입을 촉진하고 개개인의 학습역량을 향상시킬 수 있는 방안들을 개발할 것을 제언한다.

• Journal of Computational Design and Engineering
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• 제1권3호
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• pp.213-222
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• 2014

This paper reviews and identifies issues in the application of virtual commissioning technology for automated manufacturing systems. While the real commissioning of a manufacturing system involves a real plant system and a real controller, the virtual commissioning deals with a virtual plant model and a real controller. The expected benefits of virtual commissioning are the reduction of debugging and correction efforts during the subsequent real commissioning stage. However, it requires a virtual plant model and hence still requires significant amount time and efforts. Two main issues are identified, the physical model construction of a virtual device, and the logical model construction of a virtual device. This paper reviews the current literature related to the two issues and proposes future research directions to achieve the full utilization of virtual commissioning technology.