• Biomedical Engineering Letters
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• v.8 no.4
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• pp.383-392
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• 2018

For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.389-399
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• 2014

Purpose: This study was aimed at developing a tractor-driving simulator for the safety training of agricultural tractor operators. Methods: The developed simulator consists of five principal components: mock operator control devices, a data acquisition and processing device, a motion platform, a visual system that displays a computer model of the tractor, a motion platform, and a virtual environment. The control devices of a real tractor cabin were successfully converted into mock operator control devices in which sensors were used for relevant measurements. A 3D computer model of the tractor was also implemented using 3ds Max, tractor dynamics, and the physics of Unity 3D. The visual system consisted of two graphic cards and four monitors for the simultaneous display of the four different sides of a 3D object to the operator. The motion platform was designed with two rotational degrees of freedom to reduce cost, and inverse kinematics was used to calculate the required motor positions and to rotate the platform. The generated virtual environment consisted of roads, traffic signals, buildings, rice paddies, and fields. Results: The effectiveness of the simulator was evaluated by a performance test survey administered to 128 agricultural machinery instructors, 116 of whom considered the simulator as having potential for improving safety training. Conclusions: From the study results, it is concluded that the developed simulator can be effectively used for the safety training of agricultural tractor operators.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.4
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• pp.333-341
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• 2017

The Korea Atomic Energy Research Institute (KAERI) constructed the PyRoprocessing Integrated inactive Demonstration facility (PRIDE) to carry out experiments on engineering scale pyroprocessing. PRIDE has a large processing cell that human workers are not allowed to access, and thus the equipment inside is operated from outside using remote handling systems. It is therefore essential to examine the operability and maintainability of the equipment in view of remote handling systems, and the equipment is thoroughly examined in a mockup cell before it is installed in the processing cell. If the equipment is tested in a virtual mockup rather than in a mockup cell, the development cost can be significantly reduced. The PRIDE 3D simulator was integrated for virtual verification of equipment that will be installed in the processing cell. All remote handling devices in the actual PRIDE were also virtually installed in the PRIDE 3D simulator. The 3D model of the equipment was loaded and located in the exact position in the virtual processing cell. A scenario to replace an actual electrode was implemented in the PRIDE 3D simulator. The design of the equipment and the working procedures in the scenario were successfully evaluated. The results demonstrated that the PRIDE 3D simulator can be used successfully as an alternative to actual mockup testing.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.1_2
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• pp.135-143
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• 2004

3D Graphics accelerator is usually composed of two parts, geometry engine and rasterizer. In this paper, VGE(Vector Geometry Engine) which exploits vertex-level parallelism is proposed. In VGE, Common Floating-Point Unit by adding four-FADD, four-FMUL unit and 128-vector register accelerates geometry calculation. In comparison with SH4, Performance result show that the VGE can achieve performance gain over 4.7 times. To evaluate VGE performance, we make simulator to rebuild Simple-Scalar, general purpose processor simulator. In simulator model, we use Viewperf-benchmark.

• Korean Journal of Computational Design and Engineering
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• v.9 no.3
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• pp.212-219
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• 2004

This paper presents the visualization method of the KAIST interactive bicycle simulator. The simulator consists of two bicycles of 6 DOF and 4 DOF platforms, force feedback handlebars and pedal resistance systems to generate motion feelings; a real-time visual simulator, a HMD and a beam projection system; and a 3D sound system. The system has an integrating control network with the server-client network structure for multiple simulators. The visual simulator generates dynamic images in real-time while communicating with other modules of the simulator. The operator of the simulator can have realistic visual experience of riding on a velodrome or through the KAIST campus, while being able to watch the other bicycle with an avatar.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1778-1784
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• 2010

This study investigates the criteria for assessing the vibration serviceability of highway bridges using advanced driving simulator. Reiher-Meister Curves were firstly reviewed for extended application to serviceability of highway bridges. Modified Reiher-Meister Curves were provided in this paper based on field test results and numerical analyses results. The Modified Reiher-Meister Curves were evaluated using advanced driving simulator. The new curve consisted of 4 level, A(Disturbing), B(Strongly perceptible), C(Allowable), and D(Comfortable). The new criteria will be extensively applied to design and maintain highway bridges with respect to driver condition.

• Convergence Security Journal
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• v.18 no.5_2
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• pp.53-60
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• 2018

As science and technology develops, it is expected that more precise and various weapons will be used in a much more complicate future battlefield environment. C4I is a system that provides the proper and necessary information to commanders and their staffs to recognize the battlefield situation by connecting and visualizing the complex battlefield environment and various weapon systems together. Commanders and staffs perform battle command training based on a computer or paper map to better utilize the C4I system and Command Post eXercise(CPX) is a process of the training. This is the way for them to improve command control and decision making skills. Analyzing of line of sight(LOS), identifying communication fringe area, deploying troop strength, and determining unit maneuver are highly restricted under the 2D based CPX. In recent years, however, three-dimensional (3D) CPX simulators have been developed to overcome these drawbacks. In response to this trend, this paper proposes a multi-user based CPX simulator using augmented reality (AR) glass, which can be used as a practical war game simulator.

• Transactions of the KSME C: Technology and Education
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• v.3 no.2
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• pp.83-88
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• 2015

Agricultural tractors are utilized on rough road such as rice paddy field. Therefore, static and dynamic load should be considered when simulating structural analysis with finite element analysis (FEA). But it consumes a lot of time and effort to measure dynamic load because of difficulty and complexity in modeling various field working load conditions and kinematics of machinery. In this paper, to reduce the efforts, 4-post road simulator is developed for agricultural tractor like modeling commercial vehicle. In proving ground test in our facility, I measured acceleration of front/rare axle and strain of body frame to validate input loads. The acceleration is used for defining input loads. And strain is validated with dynamics analysis including mode superposition method. As a result, I was able to calculate 4-post input road profiles, which represent similar proving ground profile with good reliability.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.118-124
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• 2010

We proposed a goods load simulator for optimum RFID distribution, which includes experiment process modeling guidelines for stable RFID scan rate, efficient cost-reduction of RFID application or even speedy management of RFID field. We show verification of this simulator using field test of distribution, and the proposed simulator has better performance than the classic method, and demonstrate the proposed is efficient method of draw up guidelines on RFID distribution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5827-5831
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• 2011

In this paper, 5Ghz microstrip patch antenna for wireless LAN is designed, fabricated, and measured. To obtain wide bandwidth and high gain, antenna parameters such as patch size(W, L), the length of the slot(C), and the slot width(D) are simulated by HFSS(High Frequency Structure Simulator). From these parameters optimized, the microstrip patch antenna is fabricated using FR-4 substrate. The measured results of the antenna are as follows: The center frequency of 5.2 GHz, insertion loss of -41.17dB, bandwidth of 258MHz, and VWSR of 1.1.