• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.813-843
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• 2008

This paper investigates the presence of long-run and short-run price asymmetries in weekly gasoline prices from January 1997 to July 2008. In accordance with distribution channels, wholesale and retail stages are analyzed separately. An approach based on TAR and M-TAR cointegration tests, which entail matching asymmetric ECMs, is employed. For wholesale prices, asymmetries in the links with crude oil prices and exchange rates are found for both ECMs in the long-run and short-run. Exchange rates appear to play more significant role than crude oil prices in explaining the short-run price asymmetry. The rise in crude oil prices or exchange rates has statistically significant major impact on the increase of wholesale prices on the second week, not immediately as expected in the concept of 'rockets and feathers'. And asymmetrically, the fall does not have any statistically significant effect on the same period. The finding seems to be somewhat unusual. However, for retail prices, asymmetry m connection with wholesale prices is only revealed in the long-run. A symmetric price adjustment can be assumed in the short-run. Contrary to the long-run asymmetry found in the wholesale stage, in the retail stage, the speed of adjustment for negative deviations toward long-run equilibrium is faster than for positive ones, which is a phenomenon not favorable to consumers.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.1-11
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• 2021

POGO is a dynamic axial instability phenomenon that occurs in liquid-propelled rockets. As the natural frequencies of the fuselage and those of the propellant supply system become closer, the entire system will become unstable. To predict POGO, the propellant (oxidant and fuel) tank in the first stage is modeled as a shell element, and the remaining components, the engine and the upper part, are modeled as mass-spring, and structural analysis is performed. The transmission line model is used to predict the pressure and flow perturbation of the propellant supply system. In this paper, the closed-loop transfer function is constructed by integrating the fuselage structure and fluid modeling as described above. The pogo suppressor consists of a branch pipe and an accumulator that absorbs pressure fluctuations in a passive manner and is located in the middle of the propellant supply system. The design parameters for its design optimization to suppress the decay phenomenon are set as the diameter, length of the branch pipe, and accumulator. Multiple-objective function optimization is performed by setting the energy minimization of the closed loop transfer function in terms of to the mass of the pogo suppressor and that of the propellant as the objective function.

• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.146-168
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• 2022

Witnessing current military conflicts in South China Sea and Eastern Europe, most defense analysts evaluate one of the most serious security threat toward the US is coming from the superpower competitions with Russia and China. The main means for such super power hegemonic competitions is military power and space power is a key enabler to maximize the efficiency and effectiveness of military employment. Reflecting above circumstances, the space hegemonic competition between the Unites States and China is spreading into all aspects of national powers. Under such an environment, R.O.K needs to significantly develop national space power to preserve life and assets of people in space. On the other hand, the R.O.K has a lot of limitations in launching space assets into orbits by land-based space rockets due to its geographic locations. The limitation of rocket launching direction, the failure to secure a significant area enough to secure safety and the limitation to secure open area enough to build associated facilities are among them. On this paper, I will suggest the need to build the 2nd space rocket launching site after analyzing a lot of short-falls the current 'Naro' space center face, compared to those of advanced space powers around the world.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.400-405
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• 2023

Currently, inverted pendulums are being studied in many fields, including posture control of missiles, rockets, etc, and bipedal robots. In this study, the vertical posture control of the pendulum was studied by constructing a rotary inverted pendulum using a 256-pulse rotary encoder and a DC motor. In the case of nonlinear systems, complex algorithms and controllers are required, but a control method using the classic and relatively simple PID(Proportional Integral Derivation) algorithm was applied to the rotating inverted pendulum system, and a simple but desired method was studied. The rotating inverted pendulum system used in this study is a nonlinear and unstable system, and a PID controller using Microchip's dsPIC30F4013 embedded processor was designed and implemented in linear modeling. Usually, PID controllers are designed by combining one or two or more types, and have the advantage of having a simple structure compared to excellent control performance and that control gain adjustment is relatively easy compared to other controllers. In this study, the physical structure of the system was analyzed using mathematical methods and control for vertical balance of a rotating inverted pendulum was realized through modeling. In addition, the feasibility of controlling with a PID controller using a rotating inverted pendulum was verified through simulation and experiment.

• The Korean Journal of Air & Space Law and Policy
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• v.24 no.2
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• pp.163-186
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• 2009

The missile technology and its development in south Korea have been restrained to the limit of 180 km by America which instead provided to Korea with security protection. In the same vein, America pressured South Korea to abort its nuclear weapons program so as to prevent another possible military encounter that can easily develop into a war between South and North Korea. This restraint was a bit relaxed when South Korea joined the Missile Technology Control Regime (MTCR) in 2001 whereby the limit was 300 km. The situation of South Korea is in much contrast with its neighbor, North Korea, which has fired Taepo Dong 1 and Taepo Dong 2 to put its alleged satellite respectively into the Earth orbit. The range of this rocket believed to be reaching more than 5,500 km, a range of the intercontinental ballistic missile, without any rein. South Korea that has just geared its full powers for its outer space industry, with the current space projects of putting its satellites into the low Earth orbit, will in future put its satellite into the geostationary orbit, 36,000 km above the Earth. To do so, such restraint had better be resolved. Korean space industry, as it is alike in other countries, started with putting and manufacturing sounding rockets, producing satellites but relying on foreign launching facilities, and learning launching capacities. Experiencing three time launchings of KITSAT, the current satellite projects of Korea are undertaken as follows: - Koreasat - STSAT - Komsat - MBSAT - COMS (Communication, Ocean, and Meteorological Satellite) Koreans waked up to the things of outer space in 2008 with the first Korean astronaut Li So-yeon, a lady bio systems engineer. Although the first Korean made rocket in cooperation with a Russian company to fire last August 2009 was a failure, it should be considered as an inevitable process for future endeavors. There are currently three outer space related laws of Korea: Aerospace Industry Development Promotion Act 1987, Outer Space Development Promotions Act 2005, and Space Damage Compensation Act 2008. The first two stemming from the two different ministries are, however, overlapping in many aspects and have some shortcomings to be improved.

• Journal of Astronomy and Space Sciences
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• v.22 no.3
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• pp.329-352
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• 2005

Long term observations of full-disk Lyman-o irradiance have been made by the instruments on various satellites. In addition, several sounding rockets dating back to the 1950s and up through the present have measured the $Lyman-{\alpha}$ irradiance. Previous full disk $Lyman-{\alpha}$ images of the sun have been very interesting and useful scientifically, but have been only five-minute 'snapshots' obtained on sounding rocket flights. All of these observations to date have been snapshots, with no time resolution to observe changes in the chromospheric structure as a result of the evolving magnetic field, and its effect on the Lyman-o intensity. The $Lyman-{\alpha}$ Imaging Solar Telescope(LIST) can provide a unique opportunity for the study of the sun in the $Lyman-{\alpha}$ region with the high time and spatial resolution for the first time. Up to the 2nd year development, the preliminary design of the optics, mechanical structure and electronics system has been completed. Also the mechanical structure analysis, thermal analysis were performed and the material for the structure was chosen as a result of these analyses. And the test plan and the verification matrix were decided. The operation systems, technical and scientific operation, were studied and finally decided. Those are the technical operation, mechanical working modes for the observation and safety, the scientific operation and the process of the acquired data. The basic techniques acquired through the development of satellite based solar telescope are essential for the construction of space environment forecast system in the future. The techniques which we developed through this study, like mechanical, optical and data processing techniques, could be applied extensively not only to the process of the future production of flight models of this kind, but also to the related industries. Also, we can utilize the scientific achievements which are obtained throughout the project And these can be utilized to build a high resolution photometric detectors for military and commercial purposes. It is also believed that we will be able to apply several acquired techniques for the development of the Korean satellite projects in the future.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.2
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• pp.203-237
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• 2011

Since USSR successfully launched its satellite "Sputnik"in 1957, many countries including US and USSR began military use of space, and engaged in arms race in space, which is against spirit and ideals of peaceful use of space as common heritage of mankind stipulated in many treaties such as Outer Space Treaty. With worsening Cold War between East and Western Bloc, this military use of space and arms race in space has been intensifying. Regarding the ideals of peaceful use of space, it is interpreted that military use of space is possible unless it does not have the purpose of aggression. The military use of space may have diverse forms such as attacking satellites in space, or attacking from satellites, making use of present and future technologies available which should include the use of nuclear and kinetic/hyper-speed weapons, laser, particle beams, near explosion, disturbance weapons in different directions (i.e., surface to space, space to space, and space to surface). Arms control is being implemented by the efforts of many countries in different formalities including legislature of international treaties under the auspices of UNCOPUOS and prohibition of weapons of mass destruction. Taking outstanding examples aiming at arms control by international community, there are confidence building measures (CBM), strengthening implementation of existing treaties, partial ban of nuclear tests, countryand regional approach, comprehensive approach and measures having legally binding force. While U.S. has surpassed other countries concerned in the area of military useof space, it withdrew from OST in early 2000s, thereby raising concern of international community. It requires concerted efforts of cooperationand implementation by international society to make sure peace of mankind and environmental conservation through arms control in space. Observing de facto possession of nuclear weapons by North Korea following series of nuclear tests and launching satellites, and efforts of launching rockets by South Korea, it is strongly needed for both countries to take part in arms control efforts by international community.