• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.703-705
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• 1996

CALS (Commerce At the Light Speed) is considered one of the most important concepts in the 21th century. In the period of CALS, the roles of telecommunication companies to prepare for CALS period. They are: development of facilities management, participation of virtual enterprise prototype, providing teleconference tool, execution of BPR, development fo customer management system.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.143-146
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• 2000

Generally, two methods can be used to correct the undesirable magnetic field of MRI. One is active shimming method and the other is passive shimming. Passive shimming method uses many magnetized shims to correct the field. And it involves hardwared for supporting shim trays and a software to calculate a field map and optimaze the locations of the shims[1]. The software is the most important part of the passive shimming system. We made a prototype of the software and tested it in a virtual situation.

• The Magazine of the IEIE
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• v.30 no.9
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• pp.59-59
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• 2003

여러기능들이 복합적으로 통합되고 있는 단일칩시스템을 설계하는데 있어 소프트웨어와 하드웨어를 가능한 일찍 통합하여 검증하는 것이 무엇보다 중요하다. 이러한 조기 통합검증에 필요한 것이 가상프로토타입(Virtual-Prototype) 이다. 본 고에서는 IP(Intellectual Property) 와 단일칩시스템(SoC : System-on-a-Chip) 설계 및 검증에서 가상프로토타입의 필요성과 역할 그리고 이에 관련된 기술들에 대해 정리하고, 프로세싱 코어가 있는 단일칩시스템을 SystemC로 가상프로토타이핑한 사례를 통해 그 유용성을 설명한다.

• The Magazine of the IEIE
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• v.30 no.9
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• pp.965-975
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• 2003

여러기능들이 복합적으로 통합되고 있는 단일칩시스템을 설계하는데 있어 소프트웨어와 하드웨어를 가능한 일찍 통합하여 검증하는 것이 무엇보다 중요하다. 이러한 조기 통합검증에 필요한 것이 가상프로토타입(Virtual-Prototype) 이다. 본 고에서는 IP(Intellectual Property) 와 단일칩시스템(SoC : System-on-a-Chip) 설계 및 검증에서 가상프로토타입의 필요성과 역할 그리고 이에 관련된 기술들에 대해 정리하고, 프로세싱 코어가 있는 단일칩시스템을 SystemC로 가상프로토타이핑한 사례를 통해 그 유용성을 설명한다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.153-158
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• 1999

In the multi-purpose lathe, the design of tilting turret slide system has an important and critical role to enhance the accuracy of the machining process. Tilting turret unit is traveled by 3-axis slide systems. There is a need to design this part very carefully. In this research, the 3-axis slide system with tilting turret unit is modeled and simulated using ADAMS software. The dynamic behavior of this system is visualized by data graphs and dynamic animations. The first step of virtual prototype which makes it possible to design economically and effectively is developed.

• Korea Information Processing Society Review
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• v.5 no.2
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• pp.35-42
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• 1998

현재 자동차 분야에서는 사용자의 욕구와 인간공학적인 측면을 얼마나 잘 반영하는 차를 만들어 내는가가 점차 중요한 요소로서 부각되어지고 있다 EK라서 이에 부합하여 많은 자동차 시뮬레이터에 관한 연구들이 진행되고 있는 실정이다 본 연구실에서는 자동차-인간 상호작용을 연구하기 위한 가상현실 시뮬레이터(VISVEC : Virtual Simulator for VEhicle Cockpit) 의 제작 Model을 개발 하였다 현재 VISVEC은 자동차 HMI Usability를 위한 시뮬레이터로서 PC를 기반으로 하여 구축되고 있다.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.473-475
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• 2003

To overcome the limitation that traditional GISs lose much information for the real world, 4-dimensional GIS has the additional reference systems including object's height and temporal dimension. This paper describes the 4-dimensional geometric object model and components. The prototype for 4-dimensional GIS consists of the data provider, manager, and renderer components. We show the virtual city that its database contains topographic maps, buildings, roads and temporal history data. This provides spatial, temporal operations and analysis functions.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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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.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.293-302
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• 2020

The purpose of this study was to evaluate the applicability of virtual reality simulation after experience of dental caries diagnosis for dental students before exposing to clinical pediatric practice. A pediatric patient model of a five-year-old child with primary dentition was developed and a caries model that is amenable to VR(virtual reality) diagnosis was organized and set-up. The dental student's were allowed to use the simulated model for fifteen minutes and their experiences were evaluated using a self-reported questionnaire to evaluate presence and usability of this application. Overall, virtual presence and appearance area of the simulation were highly scored. The result indicates that the VR model has no significant difference from the actual clinical caries regardless of grade of students, gender and VR experience. If the prototype is continuously advanced, its applicability in dental education will increase.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5375-5400
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• 2016

IOMMU is a hardware unit that is indispensable for DMA. Besides address translation and remapping, it also provides I/O virtual address space isolation among devices and memory access control on DMA transactions. However, currently commodity virtualization platforms lack of IOMMU virtualization, so that the virtual machines are vulnerable to DMA security threats. Previous works focus only on DMA security problem of directly assigned devices. Moreover, these solutions either introduce significant overhead or require modifications on the guest OS to optimize performance, and none can achieve high I/O efficiency and good compatibility with the guest OS simultaneously, which are both necessary for production environments. However, for simulated virtual devices the DMA security problem also exists, and previous works cannot solve this problem. The reason behind that is IOMMU circuits on the host do not work for this kind of devices as DMA operations of which are simulated by memory copy of CPU. Motivated by the above observations, we propose an IOMMU para-virtualization solution called PVIOMMU, which provides general functionalities especially DMA security guarantees for both directly assigned devices and simulated devices. The prototype of PVIOMMU is implemented in Qemu/KVM based on the virtio framework and can be dynamically loaded into guest kernel as a module, As a result, modifying and rebuilding guest kernel are not required. In addition, the device model of Qemu is revised to implement DMA access control by separating the device simulator from the address space of the guest virtual machine. Experimental evaluations on three kinds of network devices including Intel I210 (1Gbps), simulated E1000 (1Gbps) and IB ConnectX-3 (40Gbps) show that, PVIOMMU introduces little overhead on DMA transactions, and in general the network I/O performance is close to that in the native KVM implementation without IOMMU virtualization.