• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.1
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• pp.21-29
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• 1997

This paper describes implementation contents contents of manual/automatic complex redundancy control mothod for control of a modulation system of a Paging earth station in redundancy stracture. The existed redundancy control method usually is a automatic local control method in which the redundancy switching, including display or alarm beeping through operation of display devices or audio devices, is performed by the co-action of components or modules when the abnormal status is occurred in a modulation system. However, this method introduced in here is designed to enable use of three control modes;1) Manual mode by an operator, 2) Auto-remote mode by the Network Maagement System, through implementation of the redundancy control system composed of the redundancy control board and the redundancy switching circuit.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.24-29
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• 2001

Adaptive valve timing control is one of the promising techniques to accomplish the optimized mixture formation and combustion depending on the load and speed, which is needed to meet the future challenges in reducing fuel consumption and exhaust emissions. The behavior and the effect of adaptive valve timing control system has been investigated by computer simulation, which simulates the gas dynamics in engines. Improved fuel economy can be achieved by reduction of pumping loss under low and mid load conditions. EIVC(Early Intake Valve Closing) strategy turns out to be superior to LIVC(Late Intake Valve Closing) strategy in reducing fuel consumption. Deterioration of combustion quality can be overcome by introducing LIVO(Late Intake Valve Opening) strategy, which increases turbulent intensity in cylinders. Furthermore, LIVO can reduce HC emission by decreasing the required amount of fuel to be injected during cold start.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.145-148
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• 2008

Fuel flexibility of CFBC boiler was examined. Combustion characteristics of low grade coal, coal sludge, coal RDF mixture and RDF were compared. The operation result of a commercial 130TPH CFBC co-generation boiler burning a low grade Chinese coal were analysed. Burning characteristics of coal/RDF mixture and coal and industrial sludge mixture were studied in a 0.1MWth scale CFBC test rig. Also RDF fuel were tested in a 8TPH CFBC test facility. Though fuel characteristics were different, the combustion modes were all very stable. The temperature were maintained in between $800-950^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.153-156
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• 2008

MILD combustion has been successfully applied to gaseous fuels and few commercial systems are now in operation. Extending MILD combustion applicability to solid fuel of sawdust is the focus of the present work. The MILD combustion furnace at the University of Adelaide in Australia was used in this study. A measurement of $O_2$ and CO emissions have been carried out in parallel with consideration of NOx emission and compared in each modes of conventional natural gas combustion, natural gas MILD combustion, NOx emission in natural gas MILD combustion mode can be reduced to 20% in comparison with conventional combustion. Emission in cases of air carrying sawdust combustion and $CO_2$ carrying sawdust combustion were also compared. Air and $CO_2$ were sued as a carry gas for the sawdust. It was found that MILD conditions are possible for sawdust particles of less than $355{\mu}m$ without additional air pre-heating. It was also found that when using $CO_2$ as the carry gas the flame inside the furnace was not visible anymore and that NOx emission dropped to less than two folds.

• Journal of KSNVE
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• v.10 no.5
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• pp.819-829
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• 2000

Dynamic Characteristics of two different types of ER(electro-rheological)mounts ; flow and shear mode types are analyzed and compared. As a first step, field-dependent Bingham models of a chemically treated starch/silicone oil-based ER fluid are empirically identified under both flow and shear mode conditions. The models are them incorporated to the governing equation of the corresponding mode ER mount. For the reasonable comparison between two ER mounts, electrode parameters such as electrode gap are designed to be same. Dynamic stiffness and displacement transmissibility of each ER mount are evaluated in frequency domain with respect to the intensity of electric filed. In addition, vibration control capability of each ER mount is investigated in both frequency and time domains by employing the skyhook controller.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.275-282
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• 1999

This paper presents the current-fed inverter of a TGV-K traction system with thyristor switches using phase control and commutation techniques. The current-fed inverters have two modes of operation which consist of forced commutation and natural commutation. In forced commutation mode, at speed of less than 120km/h, commutation is forced by means of the commutation capacitors and the thyristors. Above 120km/h, the thyristors operate in natural commutation mode, according to the voltages between phases of the motors. In this paper, the power conversion theory of the TGV-K traction system and the control principle of the converter and current-fed inverter are discussed.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.449-452
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• 2009

The vision of u-City is an implementation of ubiquitous environments that makes anybody to be able to access the source of information and knowledge in anywhere and anytime with any methods. It is necessary to study the law and institution of u-City about a role of the government and local governments to have a new growth power. We need to improve the related law and institution with standardization of u-City service to regulate and coordinate diversity of main organ and business area. In this paper, we select service modes to consider the priority order of service and suggest a reform measure of law and institution classified by service models

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.186-192
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• 2001

A chevron rubber spring is used in primary suspension system for rail vehicle. The chevron spring has function which support the load carried and reduce vibration and noise in operation of rail vehicle. The computer simulation using the non-linear finite element analysis program MARC executed to predict and evaluate the load capacity and stiffness for tile chevron spring. The appropriate shape and material properties are proposed to adjust the required characteristics of chevron spring in the three modes of flexibility. Also, several samples of chevron spring are manufactured and experimented. It is shown that the predicted values agree well tile results obtained from experiments.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.897-898
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• 2006

This paper proposes a new power-stage circuit that can be available for modularization of the power regulator which is used at the software-controlled unregulated bus system. And we analyze the proposed power-stage operation according to its operating modes and verify it by performing software simulation and hardware experiment using prototype. By constructing a parallel-module converter which is composed of proposed power-stages, we verify the operations and usefulness of the proposed power-stage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.535-538
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• 2002

We simulated Frequency-shifted feedback laser using AOM inside the cavity. We analyze instantaneous oscillation frequency at peak spectral intensity and Comb bandwidth of output spectrum from Wigner-Ville distribution of intracavity electric field. The Comb bandwidth is defined as the product of the saturation-broadened bandwidth and the total resonant modes contributing to FSF operation.