• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.750-755
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• 2011

The ignition characteristics of liquid rocket engine thrust chambers which have been developed by domestic technology were analyzed. Analysis results showed that low frequency fluctuation appeared in a partial ignition range according to different temperature profiles and vaporous state in the oxidizer manifold with startup sequences. This low frequency fluctuation wasn't developed as a malfunction factor, but this fluctuation is thought to be taken a continuous concern considering interfaces with engine system and launch vehicle.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.73-78
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• 2012

The ignition characteristics of liquid rocket engine thrust chambers which have been developed by domestic technology were analyzed through hot-firing tests. Thrust chambers used in hot-firing tests have different characteristics in terms of the injector for ignition, film cooling method and the position of the oxidizer inlet. Also, these thrust chambers used their respective startup sequences. Analysis results showed that according to temperature profiles of the oxidizer manifold, low frequency fluctuation was appeared in ignition area. This low frequency fluctuation didn't give rise to violent malfunction of the thrust chamber, but the continuous observation as a concern parameter in the side of interfaces with engine system and launch vehicle should be demanded.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.3
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• pp.1-8
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• 2016

It was examined that start-up characteristics of a staged combustion cycle engine powerpack. Among various parameters, valve opening time was considered as a main factor affecting the start-up characteristics. Using monte-carlo method, characteristics variation was analyzed when the valve opening time deviates from the nominal value. As a result, the main fuel valve opening time and the start turbine ending time were significant associated with the startup characteristics. When separating main fuel valve opening time and start turbine stop time, main fuel valve opening time was an important factor. For stable operation, the main fuel valve opening time must be set one second before after driving the start turbine. Likewise, it was confirmed that the startup analysis can suggest an appropriate startup sequence for a stable startup.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.97-100
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• 2011

It is critical to set up the starting sequence of liquid rocket engines because not carefully arranged process can lead the engine damages. Thus, many efforts were made to prevent the hard start at the ignition. Hypergolic fuels are frequently used to ignite LRE and TEAL, one of the hypergolic fuel is also used for kerosene-LOx LRE ignition. However, since we are still lack of experiences igniting oxygen rich preburners of the staged combustion cycle engines, it would be helpful to estimate the TEAL ignition phenomena before the actual tests.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.62-70
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• 2015

A liquid rocket engine system can cause rapid pressure and temperature variations during the startup period. Thus the startup analysis is required to reduce time and expense for successful development of liquid rocket engine through the startup prediction. In this study, a startup analysis simulator is developed for a staged combustion cycle engine powerpack. This simulator calculates propellant flow rates using pressure and flow rate balances. In addition, a rotational speed of turbopump is obtained as a function of time by mathematical modeling. A startup analysis result shows that the time to reach a steady-state and a rotational speed at the steady-state are 1.3 sec and 27,500 rpm, respectively. Moreover it can indicate proper startup sequences for stable operation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.167-170
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• 2006

For a short time a pyre-starter should turn the blades of a turbine to the adequate rotational speed by a single operation. Through this process the pressures of the components of a propellant rise rapidly up to the operating point, and the components enter into a gas-generator. Combustion in the gas-generator occurs to keep the turbopumps working. In this research characteristic parameters of a pyre-starter which correspond to the required performance of the turbopump before the gas-generator starts to work were selected

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.69-75
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• 2016

This paper covers the result of construction and start-up tests of the KSLV(Korea Space Launch Vehicle)-II combustion chamber hot-firing test facility. This facility was constructed from 2012 to 2014. Start-up test of this facility began in the second half of 2014. Oxidizer cold flow test, fuel cold flow test and cooling water cold flow test were carried out as start-up test. Afterward, ignition test of combustion chamber was accomplished. The result of ignition test is applied to set up start-up sequence of KSLV-II combustion chamber and utilized as base line data for hot-firing test of low and normal design point.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.70-75
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• 2014

Programs of energy balance, mode analysis and transient analysis for a liquid rocket engine have been introduced. The analysis methods have been verified through comparison between the present results, and the results of the other program and experimental data. An energy balance analysis is used for engine system design at the early development phase. A mode analysis is used for decision of engine operation conditions and test conditions, and studying deviation of an engine performance. A transient analysis can predict a propellant flow rate, thrust, impulse at transient phase. It is essential to establish a startup/shut down sequence. The analysis programs will be used to develop the engines of KSLV-II.

• The Journal of the Korea Contents Association
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• v.6 no.12
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• pp.269-277
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• 2006

In this paper, we propose an interactive system that generates emotional expressions from arm gestures. By extracting relevant features from key frames, we can infer emotions from arm gestures. The necessary factor for real-time animation is tremendous frame rates. Thus, we propose processing facial emotion expression with 3D application for minimizing animation time. And we propose a method for matching frames and actions. By matching image sequences of exagerrated arm gestures from participants, they feel that they are communicating directly with the portraits.

• Cartoon and Animation Studies
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• s.23
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• pp.1-17
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• 2011

The paper analyzed the metaphoric expressions appeared in whose cinematic quality has been subjectively recognized on the global stage by winning the Oscar for Best Animated Short Film. Many contents and visual effects of the film were expressed with metaphor. Story and sequence were analyzed through the language system-based 'Conceptual Metaphor Analysis Framework'. In addition, characters have been analyzed through the 'Visual Metaphor Analysis Framework'. The framework is to analyze visual dimensions which are derived when concepts are structuredin animation. This paper has attempted to investigate and reveal patterns how animation self-organizes or how animation self-realizes through linguistic objectives. That is, it is to reveal how animation communicates with the audience from the metaphoric perspective among many conventional ones. In an animated film, metaphor is a fundamental means to connect fragmented images, produce a holistic view and therefore induce creative communication with the audience. The essential motive of metaphor which is expressed in various styles in is modern people's feeling of loss and sense of missing something. Train, bottle top, food, lost-and-found center, in-between space and lost items have significance across the movie. According to an analysis, metaphor offers simplicity and freshness as an aesthetic function. In addition, the metaphor expresses lengthy contents and various meanings implicitly, delivering an economic function. With a creative function, metaphor is a tool to generate new meanings. In other words, an animated film is a medium to inspire and move the general public as a means of communication and thinking, not just an entertainment for young generations. After all, metaphoric expressions have been used to deliver diverse and deep meanings in animated films.