• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1228-1233
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• 2005

In this paper, we present a new guidance law for a reusable launch vehicle (RLV) that lands vertically after reentry. In our past studies, a guidance law was developed for a vertical/soft landing to a target point. The guidance law, which is analytically obtained, can regenerate a trajectory against disturbances because it is expressed in the form of state feedback. However, the guidance law does not necessarily guarantee a vertical/soft landing when a dynamical system such as an RLV includes a nonlinear phenomenon owing to the atmosphere of the earth. In this study, we introduce a design of the guidance law for a nonlinear system to achieve a vertical/soft landing on the ground using the exact linearization method and solving the two-point boundary-value problem for the derived linear system. Numerical simulation confirmed the validity of the proposed guidance law for an RLV in an atmospheric environment.

• The Plant Pathology Journal
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• v.20 no.4
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• pp.302-307
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• 2004

Three pairs of specific primers were developed for rapid and precise RT-PCR detection of three seed-transmissible viruses, namely Peanut clump virus (PCV, Pecluvirus), White clover mosaic virus (WCIMV, Potexvirus) and Carrot red leaf virus (CaRLV, Luteovirus). Each primer set was found in conserved region through multiple sequence alignment in the DNAMAN. Total nucleic acids extracted from PCV-, WCMV-, and CaRLV-infected seeds and healthy plants were used for RT-PCR detection using each virus-specific primer, Sizes of PCV, WCIMV, and CaRLV PCR products were 617bp (PCV-uni5 and PCV-uni3 primers), 561bp (WCMV-CP5 and WCMV-CP3 primers), and 626bp (CL1-UP and CL2-DN primers); which corresponded to the target sizes. Nucleotides sequences of each amplified cDNA were confirmed which belonged to the original virus. This study suggests that these virus-specific primer sets can specifically amplify viral sequences in infected seeds. Thus, they can be used for specific detection of three viruses (PCV, WCMV and CaRLV) from imported seed samples for plant quarantine service.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.289-292
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• 2007

Performance of a dual mode ramjet engine based on the sensitivity analysis of design parameters (the gap between cowl and inlet spike and combustor length) was analyzed from the view points of aerodynamics and thermodynamics. A dual mode engine performing from supersonic to hypersonic (Mach no. 2 to 6) was designed in a proposed flight envelop. The design method and result were comparable to the results of the previous study, Hyperion RLV, and the CFD calculation.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.47-52
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• 1998

This study deals with guidance and control laws for an optimal reentry trajectory of a vertical landing reusable launch vehicle (RLV) in the future. First, a guidance law is designed to create the reference trajectory which minimizes propellant consumption. Then, a nonlinear feedback controller based on a linear quadratic regulator is designed to make the vehicle follow the predetermined reference trajectory, The proposed method is simulated for the first stage of the H-II scale rocket.

• Journal of Aerospace System Engineering
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• v.5 no.1
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• pp.24-29
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• 2011

The industry related to commercial space transport is growing rapidly as a futurity industry all over the world and America is leading them. If this trend continues, domestic individuals or private enterprises may plan for the commercial space transport business by adopting the advanced technology. Therefore it is necessary to make a law to control the business in our country for the industrial development and the growth related to commercial space transport. This paper provides outline for domestic commercial space transport law by the study and analysis of U.S. commercial space transport laws.

• Korean Journal of Transplantation
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• v.31 no.4
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• pp.177-181
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• 2017

Living donor liver transplantation (LDLT) has become an inevitable procedure due a shortage of deceased donors under the influence of religious and native cultures. The most important concern in LDLT is donor safety. This study reviewed the safety of LDLT donors from reported studies of morbidity and mortality. Many studies have reported mortality and morbidity rates ranging from 0% to 33% for healthy liver donors. Use of laparoscopic surgery on LDLT donors has advantages of reduced blood loss, lower postoperative morbidity and shorter hospital stay relative to conventional open surgery. There is a consensus that remnant liver volume (RLV), degree of steatosis, and donor age are the most important factors influencing donor safety. In LDLT, donor hepatectomy can be performed successfully with minimal and easily controlled complications. However, a large-scale prospective cohort study is needed to better understand the risk factors and accurately determine the complication rates for LDLT.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.1
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• pp.215-239
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• 2011

We are now entering the era of Commercial Space Transportation with the rapid commercialization of space. Commercial Space Tourism will be realized first of all in the commercial space transportation and the spacecraft is developing for it led by private enterprise such as Virgin Galatic and XCOR Aerospace. The spacecraft for space tourism is developed as Reusable Launch Vehicle(RLV). RLV Spaceship I & II manufactured by the Scaled Composites for Virgin Galatic had completed experimental flight successfully and is going to put to the operation for space travel around the year 2012. In our country, Yecheon Astro-Space Center located in Yecheon, Kyungbuk Province, signed a binding-MOU with XCOR Aerospace and going to start space travel in the year 2013 with the spacecraft LYNX MARK-II. Thus, now space travel has become a reality to us. But it is also reality that there's no study by legal basis preparing for the space tourism domestically and internationally. In this regards, this thesis dealt with legal issues related to space tourism. These are as follows : (1) the applicabe law issue that is which law between air law and space law will apply, (2) the status of space tourist issue that is space tourist can be considered as personnel of a spacecraft and/or space flight participant and has the duty to obey the order of the captain of spacecraft, (3) the responsibility of the government for the non-governmental entities such as private enterprise which involved in space tourism in case space accident occurs during the space travel, (4) license permit and supervision issue by the government (In this point, for activating the market of the space tourism, I think it is essential to guarantee the safety of the spacecraft by the government authority, though U. S. government declared that it has not certified the launch vehicle as safe for carrying crew or space flight participants), (5) registration issue, (6) space insurance issue. For all the issues mentioned above, I have studied the existing international treaties and several country's domestic law to the space by referring U.S's Commercial Space Launch Amendment Act of 2004 and New IGA of 1998 and concluded that uniform legal regime to govern these issues should be established domestically and internationally in the near future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.687-692
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• 2004

For the prediction of sloshing in the propellant tank of rocket vehicle utilized in RVT (reusable rocket vehicle testing) conducted by ISAS/JAXA, the flow field in the propellant tank during the ballistic flight was experimentally reproduced with the sub-scale model of it. The lateral acceleration as large as about 0.8 G was provided with a mechanical exciter and the deformation of liquid surface in the vessel was visualized with a high-speed camera. The several con-figurations of damping devices were installed and tested in the vessel, which should keep the ullage gas away from the outlet port. It was consequently suggested that the combination of a baffle plate and a perforated cylinder could be effective against the gas suction before the re-ignition of the engine. The sloshing phenomena were also simulated with the CFD code, called CIP-LSM. The numerical results showed good agreement with the corresponding data obtained in the experiment.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.32-42
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• 2022

The strategy to develop a launch vehicle family by bundling multiple rocket engines of a single type has been proven by SpaceX and their reusable fleet comprised of Falcon 9 and Falcon Heavy. In this study, we revisit a potential launch vehicle family out of a 35 tonf-class methalox staged combustion cycle engine and evaluate their utility and performance in various space missions. For example, a Korean version of Falcon 9 can deliver 4.7 tons of payload into 500 km SSO in an expendable mode while the payload is reduced to 2.16 tons in a sea-landing reusable mode. A Korean version of Falcon Heavy can deliver 4.4 tons into GTO when launched from the Naro Space Center, indicating that this common booster core configuration can handle Cheollian 2 albeit the high inclination. Once developed, the same methaloax engine can power the first-stage of smallsat launch vehicles and air launch vehicles.