• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.898-903
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• 2011

Units assembled in the liquid-propellant propulsion system of launch vehicles should guarantee their on- and off-design performances under the various environments as well as at the various operation modes for the launch preparation and flight of launch vehicles. Units of liquid-propellant propulsion system can be installed in launch vehicle to insert satellite(s) into target orbit(s) only under the condition that all units must pass a series of tests to confirm whether those units perform normally as designed under the environment, which may be occurred in such stages of all development and operations as development, qualification, acceptance, assembly, pre-launch preparation, launch, and flight, and whether those units have been developed according to design requirements. Requirements for such tests have been already prepared in the advanced countries in launch vehicle systems based on experiences for decades. In Korea, where is now pursuing the development of KSLV-II, the research and development of launch vehicles using liquid-propellant propulsion system have been undergone during over 10 years. Hence test requirements for the development of units consisting of liquid-propellant propulsion system should be defined and Koreanized according to the domestic environment and circumstances and based on the experiences accumulated. In this paper requirements for the tests of units in liquid-propellant propulsion system, which can be feasible domestically, have been reviewed and defined.

• Journal of Astronomy and Space Sciences
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• v.23 no.3
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• pp.217-226
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• 2006

We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours) sudden flux increases followed by slow flux decreases at the energy levels of ${\sim}50-400keV$. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases) following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases) while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases) due to the dipolarization (the stretching) on the nightside as the sawtooth flux increases (decreases). This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.

• Journal of Astronomy and Space Sciences
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• v.25 no.1
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• pp.43-52
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• 2008

As the next generation of global satellite navigation system, the Galileo project is about to witness an initial orbit validation stage as the successful test of navigation message transmission from Giove-A in 2007. The Space Geodesy division ana the Radio Astronomy division of the Korea Astronomy & Space Science Institute had collaborated on the field survey for the Galileo Sensor Station (GSS) RF environment of the proposed site near Jeju Tamla University from August 3rd to August 5th, 2006. The power spectrums were measured in full-band $(800{\sim}2000MHz)$ and in-band (E5, E6 and L1 band) in frequency domain for 24 hours respectively. Finally, we performed a time domain analysis to characterize strong in-band interference source based on the result of the previous step.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.215-218
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• 2012

We have carried out the experiment to investigate optimal drainage time of barley seeding synchronized with rice harvesting in paddy field. Number of emerged barley seedling on moist paddy field was less than that of common paddy field. It is very hard to plow using combine owing to long time to work on wet condition compared to drying condition of paddy field. According to the drainage time, growth and yield of barley were not significantly different. However, late drainage time decreased the spikes per $m^2$. Rice yield and 1,000 husked rice grain weight were not significant depending on drainage times at 15 days, 20 days and 25 days before barley seeding. The range of 1,000 husked rice grain weight was 21.7~22.2 g on different drainage conditions. In results, on considering of soil hardness and time of labor, the optimal contents of soil moisture was about 33%. This study reveals that drainage time at 20 days before barley seeding is proper to increase seedlings and yield.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.72-81
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• 2007

Quantitative structure-activity relationships (QSARs) on the pre-emergency herbicidal activity and reactivity of a series of new O,O-dialkyl-1-phenoxyacetoxy-1-methylphosphonates (S) analogues against seed of cucumber (Cucumus Sativa) were discussed quantitatively using 2D-QSAR and HQSAR methods. The statistical values of HQSAR model were better than that of 2D-QSAR model. From the frontier molecular orbital (FMO) interaction between substrate molecule (S) and $BH^+$ ion (I) in PDH enzyme, the electrophilic reaction was superior in reactivity. From the effect of substituents, $R_2$-groups in substrate molecule (S) contributed to electrophilic reaction with carbonyl oxygen atom while X, Y-groups contributed to nucleophilic reaction with carbonyl carbon atom. And the influence of X,Y-groups was more effective than that of $R_2$-groups. As a results of 2D-QSAR model (I & II) and atomic contribution maps with HQSAR model, the more length of X, Y-groups is longer, the more herbicidal activity tends to increased. And also, the optimal ${\epsilon}LUMO$ energy, $({\epsilon}LUMO)_{opt.}$=-0.479 (e.v.) of substrate molecule is important factor in determining the herbicidal activity. It is predicted that the herbicidal activity proceeds through a nucleophilic reaction. From the analytical results of 2D-QSAR and HQSAR model, it is suggested that the structural distinctions and descriptors that contribute to herbicidal activities will be able to applied new herbicide design.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.270-277
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• 2008

Vacuum is any air or gas pressure less than a prevailing pressure in an environmental or, specifically, any pressure lower than the atmospheric pressure and is used by a wide variety of scientists and engineering - including clean environment, thermal insulation, very long mean free path, plasma, space simulation[1]. The space environment is characterized by such a severe condition as high vacuum, and very low and high temperature. Since a satellite will be exposed to such a space environment as soon as it goes into its orbit, space environmental test should be carried out to verify the performance of the satellite on the ground under the space environmental conditions. A general and widely used method to simulate the space environment is using a thermal vacuum chamber which consists of vacuum vessel and thermally controlled shroud. As indicated by name of vacuum chamber, the vacuum technology is applied to design and manufacture of the thermal vacuum chamber. This paper describe the vacuum technology which is applied to space business.

• Journal of the Korean earth science society
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• v.23 no.5
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• pp.416-423
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• 2002

The concentrations of dimethylsulfide (DMS) and carbon disulfide (CS$_2$) were measured concurrently with relevant environmental parameters at Kosan, Cheju during Apr 2001. Results of our analysis indicate that the combined temporal variations of both DMS and CS$_2$ record three distinctible patterns that are separable from each other. For instance, DMS behaved very similarly to CS$_2$ during the 1st (5${\sim}$18 Apr) and 3rd period (23${\sim}$26 Apr). The pronouncingly high concentration of CS$_2$ was maintained during the first period, but DMS values peaked mostly during the third period. It was furthermore striking to find that changes in DMS levels occurred in an opposite direction relative to CS$_2$ during the 2nd period. Although most of these variabilities appear to be associated with the interaction of source/sink processes and the air parcel movement, certain aspects of their behavior are found to be highly complicated enough to account for.

• Korean Journal of Remote Sensing
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• v.15 no.2
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• pp.131-146
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• 1999

The satellite visible data have been successfully applied to study the ocean color. Another ocean color sensor, the Ocean Scanning Multi-spectral Imager (OSMI) on the Korea Multi-Purpose Satellite (KOMPSAT) will be launched in 1999. In order to understand the characteristics of future OSMI images, we have first discussed the simulation models and procedures in detail, and produced typical patterns of radiances at visible bands by using radiative transfer models. The various simulated images of full satellite passes and Korean local areas for different seasons, water types, and the satellite crossing equator time (CET) are presented to illustrate the distribution of each component of radiance (i.e., aerosol scattering, Rayleigh scattering, sun glitter, water-leaving radiance, and total radiance). A method to evaluate the image quality and availability is then developed by using the characteristics of image defined as the Complex Signal Noise Ratio (CSNR). Meanwhile, a series of CSNR images are generated from the simulated radiance components for different cases, which can be used to evaluate the quality and availability of OSMI images before the KOMPSAT will be placed in orbit. Finally, the quality and availability of OSMI images are quantitatively analyzed by the simulated CSNR image. It is hoped that the results would be useful to all scientists who are in charge of OSMI mission and to those who plan to use the data from OSMI.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.297-309
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• 2007

The first Korean geostationary weather satellite, Communications, Oceanography and Meteorology Satellite (COMS) will be launched in 2008. The ground station for COMS needs to perform geometric correction to improve accuracy of satellite image data and to broadcast geometrically corrected images to users within 30 minutes after image acquisition. For such a requirement, we developed automated and fast geometric correction techniques. For this, we generated control points automatically by matching images against coastline data and by applying a robust estimation called RANSAC. We used GSHHS (Global Self-consistent Hierarchical High-resolution Shoreline) shoreline database to construct 211 landmark chips. We detected clouds within the images and applied matching to cloud-free sub images. When matching visible channels, we selected sub images located in day-time. We tested the algorithm with GOES-9 images. Control points were generated by matching channel 1 and channel 2 images of GOES against the 211 landmark chips. The RANSAC correctly removed outliers from being selected as control points. The accuracy of sensor models established using the automated control points were in the range of $1{\sim}2$ pixels. Geometric correction was performed and the performance was visually inspected by projecting coastline onto the geometrically corrected images. The total processing time for matching, RANSAC and geometric correction was around 4 minutes.

• The Journal of Korean Philosophical History
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• no.59
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• pp.287-312
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• 2018

Confucianism which pursues the right relationship between person and person, depicts the ideal that moral individuals contribute to community development. In the 16th century, Toegye Yi Hwang, the authority of Korean Confucianism, reflected his educational intentions and interests and made the whole of the body of Confucianism and the whole process of the study into a series of 10 paintings 'Ten Diagrams of Sage Learning'. The purpose of the education which is claimed in the 'Ten Diagrams of Sage Learning' is to become a saint, and it ultimately coincides with the purpose of moral education which is to be introspective and practical moral man. The whole theme of 'Ten Diagrams of Sage Learning' is related to revealing the principles of humanity and morality in order to restore human nature on the basis of piety. Piety(敬) is also a purpose and a method of self-discipline, and is the main content. The method of education for traditional confucianism is aiming for the organic integration of purpose, content and method of education and reveals the consistency of the combination of knowledge and behavior in content and method. Exploring the universal value of traditional culture and re-raising moral culture that is important in traditional education is to discuss that what is valid for the present and the future is derived from the past tradition. That may be useful in solving today's educational problems. Especially, it is very meaningful to adopt a reflective approach to cultivate talented people who can 'realize oneself' and 'care for the community' which is the ultimate goal of education through analyzing the essence of moral education pursued by traditional education.