• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.3
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• pp.171-180
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• 2020

This paper presents the implementation and control methods of a battery simulator. The proposed battery simulator can emulate the dynamic characteristics of any actual battery using the second RC ladder model of the equivalent circuit. Moreover, it can emulate the variation of impedance, which is the result of the change of battery characteristics due to the aging effect. The parameters of the battery simulator can be derived from the sequence of tests of the actual battery or only from the data supplied by the battery manufacturer. Proposed methods for the battery simulator are tested by extensive experiments. Test results show that the proposed battery simulator can emulate not only the dynamic characteristics but also the aging effects of the actual battery in real time.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.108-110
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• 2002

Power System deregulation has become a worldwide trend which introduces competition in electric power system in order to realize efficient electricity production and investment. In this regard, it is very important to develop an electricity market simulator so that it is to analyze power market and study bidding strategies, market operation and market power and train market participants. In this paper, we introduce general functions and a structure of market simulator, also design the framework of the Korean market simulator based on core concepts of electricity market simulator.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.117-124
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• 2011

The train control is a facility to ensure safe train operation, and its safety is the most important factor to determine whether introduced in railway authorities. Therefore, in order to improve practical usability in the business, safety analysis and evaluation of train control system and train control related core technologies are needed. In this paper, we develop wireless communication based train separation control simulator, the simulator traces trains in real-time, and produces train movement authorities with their position and speed information, and then calculates static and dynamic speed profiles. Trains in the simulator are controlled in real-time by these profiles. In the paper, simulator configuration, train control algorithm and simulation results under simulated environment are presented.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1236-1240
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• 2004

Thermal vacuum test for satellites should be performed before launch to verify the feasibility of satellites' operation in a harsh space environment which is represented as an extremely cold temperature and vacuum condition. A large space simulator(${\Phi}8m{\times}L10m$) has been demanded to accomplish the thermal vacuum test for the huge satellites designed in compliance with the national space program of Korea. In this paper, the design and calculation of thermal shroud which is the core part of large space simulator were discussed. The characteristics of the large space simulator being constructed at Korea Aerospace Research Institute(KARI) were depicted.

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.54.2-54.2
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• 2003

• Wind and Structures
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• v.26 no.3
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• pp.179-190
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• 2018

Translation of tornadoes is an important feature in replicating the near-ground tornado flow field which has been simulated in previous studies based on Ward-type tornado simulators using relative motion of the ground plane. In this laboratory investigation, effects of translation on the near-ground tornado flow field were studied using the ISU Tornado Simulator that can physically translate over a ground plane. Two translation speeds, 0.15 m/s and 0.50 m/s, that scale up to those corresponding to slowly-moving tornadoes in the field were selected for this study. Compared with the flow field of a stationary tornado, the simulated tornado with translation had an influence on the spatial distribution and magnitude of the horizontal velocities, early reversal of the radial inflow, and expansion of the core radius. Maximum horizontal velocities were observed to occur behind the center of the translating tornado and on the right side of its mean path. An increase in translation speed, resulted in reduction of maximum horizontal velocities at all heights. Comparison of the results with previous studies that used relative motion of the ground plane for simulating translating tornadoes, showed that translation has similar effects on the flow field at smaller radial distances (~2 core radius), but different effects at larger radial distances (~4 core radius). Further, it showed that the effect of translation on velocity profiles is noticeable at and above an elevation of ~0.6 core radius, unlike those in studies based on the relative motion of the ground plane.

• Wind and Structures
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• v.11 no.2
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• pp.75-96
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• 2008

A better understanding of tornado-induced wind loads is needed to improve the design of typical structures to resist these winds. An accurate understanding of the loads requires knowledge of near-ground tornado winds, but observations in this region are lacking. The first goal of this study was to verify how well a CFD model, when driven by far field radar observations and laboratory measurements, could capture the flow characteristics of both full scale and laboratory-simulated tornadoes. A second goal was to use the model to examine the sensitivity of the simulations to various parameters that might affect the laboratory simulator tornado. An understanding of near-ground winds in tornadoes will require coordinated efforts in both computational and physical simulation. The sensitivity of computational simulations of a tornado to geometric parameters and surface roughness within a domain based on the Iowa State University laboratory tornado simulator was investigated. In this study, CFD simulations of the flow field in a model domain that represents a laboratory tornado simulator were conducted using Doppler radar and laboratory velocity measurements as boundary conditions. The tornado was found to be sensitive to a variety of geometric parameters used in the numerical model. Increased surface roughness was found to reduce the tangential speed in the vortex near the ground and enlarge the core radius of the vortex. The core radius was a function of the swirl ratio while the peak tangential flow was a function of the magnitude of the total inflow velocity. The CFD simulations showed that it is possible to numerically simulate the surface winds of a tornado and control certain parameters of the laboratory simulator to influence the tornado characteristics of interest to engineers and match those of the field.

• Journal of Astronomy and Space Sciences
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• v.27 no.2
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• pp.135-144
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• 2010

In this paper, we present the result of preliminary design of tracking mount for ARGO-M which is a movable satellite laser ranging (SLR) system developed by Korea Astronomy and Space Science Institute (KASI). The tracking mount consists of a couple of core parts such as driving motors, encoders and bearings, and the requirements of each parts are determined on the basis of the technical consideration. 2D and 3D models for tracking mount were preliminarily designed using the selected core parts. In order to evaluate the validity of the preliminarily design, the simulator to test the elevation axis was designed and manufactured. The test to check the tracking performance and system accuracy of the simulator was performed, and it was confirmed that the preliminary design meets the operating specifications. Additionally, it was found that the repetitive errors and hysteresis errors need to be improved by the additional control algorithm.

• Electronics and Telecommunications Trends
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• v.39 no.2
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• pp.77-92
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• 2024

The 3GPP (3rd Generation Partnership Project) mobile communication standard has emerged as a leading standard in the market over the past 20 years, driving continuous development in protocol stacks and libraries that support the standard within simulation software for communication network research. We summarize and analyze seven communication network simulators that support the 3GPP standard specifications related to core network technologies. Through comparisons, we aim to offer valuable insights for researchers and engineers engaged into research and development related to mobile communication networks based on 3GPP standards. Our findings can provide assistance for making informed decisions on simulator selection.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.4
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• pp.153-164
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• 2019

This paper presents the development of an end-to-end numerical simulator for signal design of the next generation global navigation satellite system (GNSS). The GNSS services are an essential element of modern human life, becoming a core part of national infra-structure. Several countries are developing or modernizing their own positioning and timing system as their demand, and South Korea is also planning to develop a Korean Positioning System (KPS) based on its own technology, with the aim of operation in 2034. The developed simulator consists of three main units such as a signal generator, a channel unit, and a receiver. The signal generator is constructed based on the actual navigation satellite payload model. For channels, a simple Gaussian channel and land mobile satellite (LMS) multipath channel environments are implemented. A software receiver approach based on a commercial GNSS receiver model is employed. Through the simulator proposed in this paper, it is possible to simulate the entire transceiver chain process from signal generation to receiver processing including channel effect. Finally, numerical simulation results for a simple example scenario is analyzed. The use of the numerical signal simulator in this paper will be ideally suited to design a new navigation signal for the upcoming KPS by reducing the research and development efforts, tremendously.