• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.5
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• pp.452-459
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• 2007

This paper presents the flight control system using a PC104 with GPS and IMU. This System includes an Auto/Manual conversion module by PIC16 for safety, and homing type guidance algorithm to flight toward a scheduled target. We verify the performance of the flight control system via ground test, and present the possibility of application into UAV control system via comparison with the commercial system.

• Journal of the military operations research society of Korea
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• v.26 no.2
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• pp.28-38
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• 2000

This research investigates a kill probability model for the performance evaluation of guided missile system, and also develops graphical user interface for the input and output of the model based on the visual object-oriented programming application. The major simulation events used in this research are missile guidance homing point, burst points, and kill mechanism(direct kill, blast kill and fragment kill). For the user interface, we also design and implement the visualization system that can show the graphic style of the kill probability attained by the model. The results of sample run are shown, but these could be improved to be better with visual simulation which can visulaize all the simulation process of the model.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2160-2164
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• 2008

Miniature Joule-Thomson cryocoolers have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. The cool-down time, the temperature at the cold end, the running time and the gas consumption are the important indicators of the performance of the J-T cryocooler. In this study, the initial cool-down stages of the J-T cryocooler were investigated by numerical simulations. The results show the effects of the initial charging pressures of gas on the cool-down time and the temperature at the cold end and the gas consumptions.

• Journal of the military operations research society of Korea
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• v.23 no.1
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• pp.1-13
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• 1997

This research investigates a kill probability model for the performance evaluation of guided missile system, and also develops the user interface implementation for the output of the model based on the visual object-oriented programming application. This paper describes in detail the methodology for the kill probability attained by a missile warhead detonating near an airborne target. The major simulation events used in this research are missile guidance homing point, burst points, and kill mechanism(direct kill, blast kill and fragment kill). For the user interface, we also design and implement the visualization system that can show the graphic style of the kill probability attained by the model. This research will bridge the gap between the sophisticated kill probability model and users who want to see the results interactively with visualization, which can benefit many of other military systems. Some examples are shown, but these will be improved to be better with visual simulation which can visualize all the simulation process of the model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.332-340
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• 2011

A missile with a strapdown seeker should properly estimate line-of-sight(LOS) rate using its attitude information and the look angle of the seeker because LOS rate information in an inertial coordinate system, which is used for a proportional navigation(PN) homing guidance, can not be obtained directly. However, an unnecessary feedback loop(Parasite Loop) is formed in the guidance and control loop, and it may cause the guidance performance degradation or even the unstability of the system(Parasite Effect). This paper presents estimation methods for the LOS rate information and effective ways to minimize the parasite effect using Routh-Hurwitz stability criterion. Various numerical simulations are also included to verify the proposed methods.

• Progress in Superconductivity and Cryogenics
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• v.11 no.1
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• pp.55-59
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• 2009

Miniature Joule-Thomson refrigerators have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. The thermodynamic performance of J-T refrigerator highly depends on the hydraulic and heat transfer characteristics of the recuperative heat exchanger. The typical recuperative heat exchanger of the J-T refrigerator has the double helical tube and fin configuration. In this study, effectiveness-NTU approach was adopted to predict the thermodynamic behaviors of the heat exchanger for the J-T refrigerator. The thermodynamic properties from the REFPROP were used to account the real gas effects of the gas. The results show the effect of the operating conditions on the performance of the heat exchanger and refrigerator for the given heat exchanger. The influences of mass flow rate and the supply pressure on the effectiveness of heat exchanger and the ideal cooling capacity are discussed in details.

• Journal of Korea Technology Innovation Society
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• v.22 no.2
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• pp.220-241
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• 2019

In order to provide theoretical guidance to research in platform strategy, we build the conceptual framework based on the organizational ecology and analyze symbiotic/competitive relationship between platform entities. Platform owner and service provider (i.e. complementors) make symbiotic relationship, where platform owner provide service provider user-base and platform resources such as marketing tools and platform technology, and service provider provide platform owner services which users utilize. In addition to symbiotic relationships, platform owner has competitive relationship with other platform owners, and service provider builds competitive relationship with other service providers. In these relationships, the strategy of platform owner affects service provider and service provider builds a strategy for their own survival and success. This type of interaction makes competitive dynamics in platform. However, previous platform literature focuses on strategies to enhance network effect from the perspective of platform owner. Thus, there is little attention on interaction among the service providers. Using the framework based on community ecology of organizational ecology, we analyze interaction and strategy between platform owner and service provider in the viewpoint of platform openness strategy and platform pricing strategy. This research contributes to the literature of platform strategy by providing a theoretical framework based on organizational ecology to deeply understand the dynamics of platform.