• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.100-105
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• 1998

This paper proposes a new control strategy of bidirectional uninterruptible power supply (UPS) with the performance of active power filter which compensates the harmonics and reactive power. With only one power stage, it is working simultaneously as the AC/DC rectifier/battery charger and DC/AC inverter to the operation of battery charging or back-up power supplying. Therefore the operation of the proposed system can be divided into the modes, such as the active power filter mode and the battery back-up power mode. And a novel closed-loop control strategy is used to calculate the reference current. The performance of the proposed 5[kVA] system is verified by the simulation and experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.511-512
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• 2007

The monitoring system has won acceptance as a premium mark that identifies the highest standard of product quality in advanced industry. The TOP features with multi-I/O ports and VGA & RCA TV-out ports supporting mirroring & multiple dual-display modes by windows 0/5. With the choice of versatile stands, panel mount, or VESA wall-mount swing arm and connecting to modem. Wireless keyboard, Customer Display and Card Reader, is your idea Panel system for the application of TOP(Touch Operation Pannel), KIOSK, or Office / Factory Automation. TOP is the hardware and software product that transacts all kind of functions for advanced technology equipment to button, switch, voice and graph etc so that let consumer use easily Industrial HMI System Touch Panel. System characteristics: Easy of use and flexibility to the user, Present a high value solution and advanced function for many Application, Factory Automation, Office Automation, Building Automation System, Information Service System, etc. Analog Touch - 2MB Flash Memory for Saving Screen Data - RS-232C/422 Serial Port - Multi Language Support.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.876-882
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• 2014

This study investigates an efficient method to estimate the total acoustic radiation power of submerged circular cylindrical structures. Since the acoustic radiation power of submerged vehicles can be changed during the operation, the estimation for its monitoring onboard is required to accomplish the missions. The total acoustic radiation power is estimated using the measured velocity and the calculated radiation efficiency of the surface which consists of submerged rectangular plate elements. Experiments are carried out to validate the estimation approach. Comparisons of the estimation results with the measurements show that they are in a good agreement for the mid-high frequency range and match well for the cases of different excitation locations which correspond to the different operation modes of underwater vehicles as well. Therefore, this estimation method can be applied effectively to the development of the radiated noise monitoring-system.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1413-1428
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• 2019

In this paper, a novel zero-voltage and zero-current switching (ZVZCS) interleaved two switch forward converter is proposed. By using a coupled-inductor-type smoothing filter, a snubber capacitor, the parallel capacitance of the leading switches and the transformer parasitic inductance, the proposed converter can realize soft-switching for the main power switches. This converter can effectively reduce the primary circulating current loss by using the coupled inductor and the snubber capacitor. Furthermore, this converter can reduce the reverse recovery loss, parasitic ringing and transient voltage stress in the secondary rectifier diodes caused by the leakage inductors of the transformer and the coupled inductance. The operation principle and steady state characteristics of the converter are analyzed according to the equivalent circuits in different operation modes. The practical effectiveness of the proposed converter was is illustrated by simulation and experimental results via a 500W, 100 kHz prototype using the power MOSFET.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.460-468
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• 2008

Recent activities on the scramjet and rocket-ramjet combined-cycle engine of Japan Aerospace Exploration Agency(JAXA) are herein presented. The scramjet engines and combined-cycle engines have been studied in the world and JAXA has also studied such the engines experimentally, numerically and conceptually. Based on the studies, 2 to 3 m long, hydrogen-fueled engine models were designed and tested at the Ramjet Engine Test Facility(RJTF) and the High Enthalpy Shock Tunnel(HIEST). A scramjet engine model was tested in Mach 10 to 14 flight condition at HIEST. A 3 m long scramjet engine model was designed to reduce a dissociation energy loss in a high temperature condition. Drag reduction by a tangential injection and two ways of a transverse fuel injection were examined. Combustor model tests at three operating modes of the combined-cycle engine were conducted, demonstrating the combustor operation and producing data for the engine design at each mode. Aerodynamic engine model tests were conducted in a transonic wind tunnel, demonstrating the engine operation in the ejector-jet mode. A 3 m long combined-cycle engine model has been tested in the ejector-jet mode and the ramjet mode since March 2007. Carbon composite material was examined for application to the engines. Production of the cooling channel on a nickel alloy plate succeeded by the electro-chemical etching.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.29-36
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• 2023

This paper shows a design of a gripper with an adjustable working area to depalletize a delivery cardboard box of various sizes. The gripper should pick the box with only one flat surface to lift the boxes stacked close to each other. The lift force of the gripper is the vacuum suction force. To handle boxes of various sizes, the gripper adjusts the working area. The gripper operates four vacuum generators independently. The simultaneous rotation on different axes of four gripper-arms with suction cups moves the position of suction force. The six operation modes of the gripper are divided into the size of the working area. The operation mode is determined according to the size of the top side of the box. Experiments are conducted by lifting the box of various sizes. The gripper can pick the box of various sizes without vacuum leaks from unused cups. Also, the experiments verify the improvement of stability of the box by adjusting the working area of the gripper. The gripper can lift the box without deformation of the box by adjusting the working area.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.10-17
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• 2010

In a passive sonar, the improvement of detection performance by using noise cancellation is usually a important problem. In this paper, we have analyzed the own-ship noise cancellation in the two operation modes which are used in the HMS system. In the operator mode, an adaptive line enhancer(ALE) is applied to improve the tonal detection by using broadband noise cancellation and the normalized least mean square(NLMS) algorithm is applied to the design of an adaptive filter. The reference input that is correlated with a primary input can be used to remove the noise incident on the observation directionin the automatic mode. Computer simulations with real sea that data show that the proposed adaptive noise canceller has good performance in passive detection under HMS operation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.1-11
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• 1999

Considerations of partition coefficients, selectivity, biocompatibility, and waste generation are important in selection of appropriate solvents to be used for extractive recovery of products from fermentation broths. Several selection criteria can be used based upon the nature of different species present in the broth. These criteria, along with examples of specific case studies, were presented. These serve not only in screening of useful solvents, but also in pointing to the specific modes of operation of recovery-coupled bioprocesses.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.144-154
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• 1996

Proposed numerous algorithms for the policing function have mainly focused on their performances. Besides their performance evaluation, however, the VLSI-implementation of these algorithms is worth consideration as well. Although, no algorithms for the policing function have been standardized up to now, ITU-T I.371 suggests two examples of algorithms, the Virtual Scheduling Algorithm (VSA) and the Continuous State Leaky Bucket algorithm. In this paper, we suggest the architecture of a policing device implementing the VSA among various algorithms for the peak cell rate policing and discuss some issues on the implementation. We also present how to select the policing modes of the two devices used to realize various policing schemes and show the experimental results obtained under four different peak cell rate values to confirm that the device performs the policing function satisfactorily. We exploit the priority encoder to run the algorithm in parallel instead of sequentially, which reduces the operation time to a great extent.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.566-572
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• 2013

A microgrid is a small scale power system. The microgrid is operated in two operation modes, the grid-connected mode and the islanded mode. In the islanded mode, the frequency of a microgrid should be maintained constantly. For this, the balance between power supply and power demand during islanded mode should be met. In general, energy storage systems (ESSs) are used to solve power imbalance. In this paper, the frequency control effect of a Lithium-ion battery energy storage system (Li-ion BESS) has been tested on the hardware-in-the loop simulation (HILS) system environment.