• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.219-222
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• 2009

Pyrostarters play a role as a turbopump starter in liquid propellant propulsion systems by supplying pressurized gas to power turbines for engine start. A rupture disk in pyrostarters, which is usually installed behind a nozzle throat, not only isolates the charged solid propellants from the external environment but also improves the ignitability of the solid propellants by increasing a chamber pressure at the beginning of combustion. Experimental tests have been performed to study the effects of rupture disk thickness, depth and shape of scores, and pressure build-up rates on burst pressures and burst diameters. The experimental results show that the developed rupture disk fulfills the performance requirements expected in a real operational condition.

• Journal of Environmental Science International
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• v.10 no.3
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• pp.217-223
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• 2001

Where no records are available at a site, a preliminary estimate may be made from relations between floods and catchment chatacteristics. A number of these chatacteristics were chosen for testing and were measured for those catchments where mean annual flood estimates were available. Although the improvement using extended data in regression of flood estimates on catchment characteristics was small, this may be due to the limitations of the regression model. When an individual short term record is to be extended, more detailed attention can be given; an example is presented of the technique which should be adopted in practice, particularly when a short term record covers a period which is known to be biassed. A method of extending the peaks over a threshold series is presented with a numerical example. The extension of records directly from rainfall by means of a conceptual model is discussed, although the application of such methods is likely to be limited by lack of recording raingauge information. Methods of combining information from various sources are discussed in terms of information from catchment characteristics supplemented by records. but are generally applicable to different sources of information. The application of this technique to estimating the probable maximum flood requires more conservative assumptions about the antecedent condition, storm profile and unit hydrograph. It is suggested that the profile and catchment wetness index at the start of the design duration should be based on the assumption that the estimated maximum rainfall occurs in all durations centered on the storm peak.

• Journal of architectural history
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• v.10 no.2 s.26
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• pp.35-54
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• 2001

This study concerns especially Choryang-Weagwan which was the largest Japanese House left in Pusan through Chosun Dynasty. Choryang-Waegwan was known to have been jointly constructed by Korean and Japanese carpenters. Therefore, Weagwan was a place for exchange of architectural tradition (special features such as sliding door and straw mat) between Korean and Japan. Judging from this point of view, It is certain that mutual influences helped to shape architecture of Choryang-Weagwan. After establishment Choryang- Weagwan was gradually extended, owing to the prosperity of trade with Japan. But since late 18th century government of Chosun did not give as much care to maintaining Choryang- Weagwan as a result of deteriorating condition of commercial and diplomatic relations with Japan. From the beginning of Choryang- Weagwan construction, Superintendents of the construction were called Hun-do and Byl-cha, who acted as official interpreters as well. And, during construction works, they were called Gamdong-gwan, At the start of construction, Weagwan was built partly in Japanese-style by the carpenters from Tokugawa Shogunate. But as time passed, the participation rate of Japanese carpenters diminished gradually. After 1831, Japanese technician vanished extremely and repairing construction was continued by the Korean workers only.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.35-44
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• 2011

Mathematical modelling for liquid rocket engine(LRE) main components were conducted to predict the dynamic characteristics when the LRE operates at the transient condition, which include engine start up, shut down, or thrust control. Propellant feeding system is composed of fuel and oxidizer feeding components except for regenerative cooling channel for the fuel circuit. Components modeling of pump, pipe, orifice, control valve, regenerative cooling channel and injector was serially made. Hydraulic tests of scale down component were made in order to validate modelling components. The mathematical models of engine components were integrated into LRE transient simulation program in concomitant with experimental validation.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.188-196
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• 2014

The spray and combustion characteristics of n-dodecane fuel were investigated in a CVCC (constant volume combustion chamber). The selection of ambient conditions for the spray followed ECN (engine combustion network) guidelines, which simulates the ambient condition of diesel engines at start of fuel injection. ECN is a collaboration network whose main objective is to establish an internet library of well-documented experiments that are appropriate for model validation and the advancement of scientific understanding of combustion at conditions specific to engines. Therefore repeatability of the experiments with high accuracy was important. The ambient temperature was varied from 750 to 930 K while the density was fixed at around $23kg/m^3$. The injection pressure of the fuel was varied from 500 to 1500 bar. The spray was injected in both non-reacting ($O_2$ concentration of 0%) and reacting conditions ($O_2$ concentration of 15%) to examine the spray and the combustion characteristics. Direct imaging with Mie Scattering was used to obtain the liquid penetration length. Shadowgraph was implemented to observe vapor length and lift-off length at non-reacting and reacting conditions, respectively. Pressure data was analyzed to determine the ignition delay with respect to the spray and ambient conditions.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.9
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• pp.57-66
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• 1994

In this paper, we present an iterative learning method of compensating for position sensor error. The previously known compensation algorithms need a special perfect position sensor or a priori information about error sources, while ours does not. to our best knowledge, any iterative learning approach has not been taken for sensor error compensation. Furthermore, our iterativelearning algorithm does not have the drawbacks of the existing interativelearning control theories. To be more specivic, our algorithm learns an uncertain function itself rather than its special time-trajectory and does not reuquest the derivatives of measurement signals. Moreover, it does not require the learning system to start with the same initial condition for all iterations. To illuminate the generality and practical use of our algorithm, we give the rigorous proof for its convergence and some experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.9 s.114
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• pp.964-970
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• 2006

Micro gas turbine(MGT) has received attention recently as small-scale distributed power sources. With characteristics such as their small size, lightweight, low maintenance cost and minimal vibrations during operation, they are expected to become widespread in a wide range of ' applications, including residential and small-scale industrial use. It is very easier to start-up and stop the MGT system which is the friendly environmental power system has just below the 9ppm NOx emmission and good quality of noise level. The exhaust heat emitted by the MGT is in the form of about $300^{\circ}C$ clean exhaust gas. The exhaust gas is suitable for absorption chiller/heater system. 1 has researched performance characteristics of the 60 kW class MGT-absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.6
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• pp.402-411
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• 2016

The concept of the meridian system is originated from an empirical, systematic references in the clinical setting, which does not always require anatomical features. As the principles of systems biology are mainly associated with regulating the body's internal environment to maintain a stable condition, they are closely similar to the theory of the meridian system. In this review, I describe the origin of the concept of the meridian system, current status of research on the meridian system and acupuncture points, and the future directions of the research. To unravel the entity of the meridian system, we have to start from understanding its origin and clinical significance. The meridian system, as a theoretical model of the indications of acupuncture points, can help to understand the interconnections that underlie the pathologies of particular diseases or symptoms. Based on the establishment of clinical data platform for acupuncture research, we can extract novel medical information from the clinical data and generate analytical models that are useful for medical knowledge discovery on acupuncture points in the future.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.65-71
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• 2016

Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system. Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch's method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

• Korean Institute of Interior Design Journal
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• no.41
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• pp.155-162
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• 2003

The factors to limit interior circumstance and the expression of the space start In the point how to provide the order in the interior space according to the intention of design. The controlling of the natural and artificial surroundings should be focused by synthesizing and analyzing the condition of circumstance, function, and emotion to provide the comfortable room to a customer in a fitness center. A fitness center aiming at the future requires various function according to it's role depending on the change of the social values. In addition, the fitness center reflecting the various regional culture according to the change of values requires the expansion of the cultural and life space. The characteristics of fitness space like this affects the mental effect of a customer with the color and quality of the materials suitable for the characteristics of grouping, continuity, symbolism, and generation as well as the unification in the total design and the simplicity of maintenance and management. The paper aims to extract factors related to the circumstance plan of the interior and to suggest it's application in the interior design. The design applicable to the circumstance plan of the interior will keep changing according to the social change and the change of the understanding along with the factors. The continuous research on the interior circumstance planning of a fitness center could be approach to develop in a systematic method and the paper will be expected to be a little step toward it.