• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2718-2722
• /
• 2008

The Roll-to-Roll system including continuous flexible thin materials and roller has its wide range of applications especially in the electronic printing industry. The industry is growing rapidly and the printing speed is also improving. However, the printing machine based on web and roller system has it own problem. As the web speed increases, the failure to wet the surface may occur and the air entrains between the liquid and the paper web. Air bubbles may remain attached to the paper web causing defects on product surface. With the development of image processing technique, the air airflow around the web and rolls can be visualized and calculated by PIV method. In our experiment, the simple web and rolls system is used to R2R simulator. The flow field is studied at various web speeds and positions. The result shows that the flow field has complicated structure with turbulent characteristic and the main trend of flow is obtained by taking time average of flow field.

• Journal of Navigation and Port Research
• /
• v.31 no.9
• /
• pp.763-769
• /
• 2007

A narrow loop noise bandwidth method is desirable to reduce the error of raw measurements due to the thermal noise. However, it degrades the performance of GPS initial synchronization such as mean acquisition time. And it restricts the loop noise bandwidth to a fixed value determined by the lower bound of the allowable range of carrier-to-noise power ratio, so that it is difficult to optimally track GPS signal. In order to make up for the weak points of the fixed-type narrow loop noise bandwidth method and simultaneously minimize the error of code and carrier measurements, this paper proposes a stepwise-type adaptive bandwidth algorithm for DGPS reference receivers. In this paper, it is shown that the proposed adaptive bandwidth algorithm can provide more accurate measurements than those of the fixed-type narrow loop noise bandwidth method, in view of analyzing the simulation results between two signal tracking algorithms. This paper also carries out sensitivity analysis of the proposed adaptive bandwidth algorithm due to the estimation uncertainty of carrier-to-noise power ratio. Finally the analysis results are verified by the experiment using GPS simulator.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.347-355
• /
• 2005

In this paper, a new continuous~time small signal model of an average current mode control is proposed. Sampling effect Is considered to obtain the proposed small signal model. By the proposed model, the high frequency response characteristics of current loop gain might be predicted accurately compared to previous models. And this leads the prediction of inductor current response of the proposed model to be accurate compared to others. In order to show the usefulness of the proposed model, prediction results of the proposed model are compared to those of the circuit level simulator, PSIM and experiment.

• Journal of the Korean Society of Safety
• /
• v.19 no.1
• /
• pp.18-22
• /
• 2004

The Fire Dynamics Simulator (FDS) was applied to a center fire in a room, of which dimensions were 1.8m${\times}$1.38m with an opening of 0.45m${\times}$1.2m doorway, to evaluate the numerical method. The time-variation of temperature at a top point of thedoorway centerline and distributions of evaluate the numerical method. The time-variation of temperature at a top point of the doorway centerline and distributions of average temperature along the doorway centerline and corner stack were compared with measurements for three different fire sizes, 7.65, 21.25 and 51.71kW. The results showed FDS predicted a very rapid fire growth compared with the experiment for all the three fire sizes, that is an importand shortcoming of FDS in compartment fire simulations. The average temperature distributions, and heights of hot gas layers and neutral planes in steady state were in reasonable agreement with the measurements.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.12
• /
• pp.2944-2951
• /
• 2013

Recently, the offshore plant has been revived by rise in oil prices and energy consumption. Due to the external environmental impact, the ballast system is essential for an offshore plant. The ballast system for the existing offshore plant, consist of pump 6EA and Ballast tank 4EA, is performed by the tilt control. However, this system is vulnerable to a failure due to the fact that a lot of equipment needs to be installed within the system. In this paper, a new concept of ballast system and the control algorithm based on IT is proposed. Simulator has been created to test the proposed system and algorithm, and as a result, it has proven that it is controlled stably.

• Nuclear Engineering and Technology
• /
• v.52 no.1
• /
• pp.87-100
• /
• 2020

Performance shaping factors (PSFs) in a human reliability analysis (HRA) are one that may influence human performance in a task. Most currently applicable HRA methods for nuclear power plants (NPPs) use PSFs to highlight human error contributors and to adjust basic human error probabilities (HEPs) that assume nominal conditions of NPPs. Thus far, the effects of PSFs have been treated independently. However, many studies in the fields of psychology and human factors revealed that there may be relationships between PSFs. Therefore, the inter-relationships between PSFs need to be studied to better reflect their effects on operator errors. This study investigates these inter-relationships using two data sources and also suggests a context-based approach to treat the inter-relationships between PSFs. Correlation and factor analyses are performed to investigate the relationship between PSFs. The data sources are event reports of unexpected reactor trips in Korea and an experiment conducted in a simulator featuring a digital control room. Thereafter, context-based approaches based on the result of factor analysis are suggested and the feasibility of the grouped PSFs being treated as a new factor to estimate HEPs is examined using the experimental data.

• Proceedings of the KIPE Conference
• /
• 2015.11a
• /
• pp.221-222
• /
• 2015

ITER AC/DC Converter의 부하는 초전도 코일이며 이에 필요한 컨버터는 총 6종류(2상한:TF, 4상한:PF, CS, VS, CCU/L, CCS)가 있다. 이중 VS 컨버터(${\pm}1050V$, ${\pm}22.5kA$)는 6대가 직렬로 접속되어 운전되고 CS 컨버터(${\pm}1050V$, ${\pm}4.5kA$)는 4대가 직렬로 접속되어 운전한다. 이들 컨버터용 제어기의 개발 단계에서 실 부하상태를 준비하는 것은 어렵기 때문에 $RTDS^{TM}$ (Real Time Digital Simulator)를 이용하여 제어 대상인 High Power 부분과 초전도 코일의 동적 시스템 모델을 HILS(Hardware-in-the-Loop Simulation)로 구축하였다. 본 논문에서는 HILS 구축에 대한 상세한 내용과 이를 활용하여 Control 시스템을 검증한 결과를 서술하였다.

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

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.2
• /
• pp.75-81
• /
• 2021

This study analyzes the resonance characteristics caused by the mutual interference between LCL filters and the grid impedance under the parallel operation of the grid-connected inverter using the LCL filter. These characteristics are verified through simulation and experiment. Two inverters are used to connect to the grid in parallel, and the system parameters, including the LCL filter, are set to the same conditions. In the case of inverters running in parallel at the point of common coupling, the presence of grid impedance causes mutual interference between the LCL filters of each inverter, and the deviation of the filter resonance frequency is analyzed to understand the parallel inverter. The correlation between the number of devices and the size of grid impedance is simulated by PSIM and verified by MATLAB. By connecting the real-time digital simulator Typhoon HILS to the DSP 28377 control board, the mutual interference characteristics are tested under the condition of two inverters running in parallel. The experimental and analysis results are the same, indicating the validity of the analysis.

• The Journal of Korea Robotics Society
• /
• v.17 no.3
• /
• pp.373-380
• /
• 2022

This paper considers a method of fast correspondence matching for iterative closest point (ICP) algorithm. In robotics, the ICP algorithm and its variants have been widely used for pose estimation by finding the translation and rotation that best align two point clouds. In computational perspectives, the main difficulty is to find the correspondence point on the reference point cloud to each observed point. Jump-table-based correspondence matching is one of the methods for reducing computation time. This paper proposes a method that corrects errors in an existing jump-table-based correspondence matching algorithm. The criterion activating the use of jump-table is modified so that the correspondence matching can be applied to the situations, such as point-cloud registration problems with highly curved surfaces, for which the existing correspondence-matching method is non-applicable. For demonstration, both hardware and simulation experiments are performed. In a hardware experiment using Hokuyo-10LX LiDAR sensor, our new algorithm shows 100% correspondence matching accuracy and 88% decrease in computation time. Using the F1TENTH simulator, the proposed algorithm is tested for an autonomous driving scenario with 2D range-bearing point cloud data and also shows 100% correspondence matching accuracy.