• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.55-63
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• 2011

Space debris is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. Since plenty of spacecrafts were launched in space after 1957, the number of space debris has been increased. According to USSTRATCOM, the number of space debris which are bigger than 10cm is more than 15,000. Recently two critical events were occurred. Which one was that China shot down their satellite using missile and the other was that t o satellite, Iridium 33 and Cosmos 2251, collided in space. Space debris environment in which KOMPSAT-2 is operating has been severe. This paper presents the status of space debris and international activity, and the comparison of conjunction assessment process between Korea Aerospace Research Institute and abroad satellite operation center.

• Archives of design research
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• no.16
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• pp.27-38
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• 1996

Environmental design is the process of creating and suggesting a new culture retlectmg the spirits and scientific know ledges of an age, so il is important for a designer, who deals environment, to perceive the present trend of science, The goal of this study is to suggest a way to recover the vanishing image in current urban environment from the viewpoint of changing world-view, The process of this study is as follows. 1. According to spatial hierarchy, the role of each space and the importance of each space in correlation with human are considered. 2. The method to undersk, nd the space from the viewpoint of new paradigm and the direction of environmental design's access are suggested. 3. The notion that introduction of semi public space In urban environment is consistent with new paradigm is demonstrated and the semi public space's role of stimulation of urban activity is emphasized. The result of this study shows a possibility that semi public space, introduced by understanding of a space on the basis of new paradigm, expands the territory of life and overcomes tile negative environmental problem like disorder, increase of entropy.

• Journal of the Korean housing association
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• v.25 no.4
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• pp.83-91
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• 2014

The purpose of this study is to clarify the characteristics between the type of daily routine and spatial configuration of activity areas in classroom and provide alternatives for space planning of activity areas in classroom of child-care centers. This study used the content analysis on daily activity plan and floor plans through field survey. Analysis on floor plans was conducted for 35 classrooms in 9 child-care centers which allowed field survey. The results of this study were as follows; There was no significant difference for classroom size according to the type of daily routine in 3 to 5-year-old classrooms. The average size of classrooms was $61.6m^2$ for care oriented type, $41.4m^2$ for indoor activity oriented type and $48.8m^2$ for group activity oriented type. There was no significant difference in composition of activity areas in classrooms according to the type of daily routine. In case of 0 to 2-year-old classrooms, they were composed of 6 activity areas including gross-motor, role play, block building, language, creative expression, exploration/manipulation. Activity area of the most low frequency was gross-motor area. In case of 3 to 5-year-old classrooms, most classrooms were composed of all the 7 activity areas including art, tone and rhythmic, block building, role play, language, math and science. Most accessible and central areas in 0 to 2-year-old classrooms were gross-motor and role play. Also, most separate areas were exploration/manipulation and block building. Most accessible and central areas in 3 to 5-year-old classroom were art and math. Also, most separate areas were tone and rhythmic and science.

• Journal of The Korean Astronomical Society
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• v.50 no.6
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• pp.167-178
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• 2017

We present a study of the inexplicit connection between radio jet activity and ${\gamma}$-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two ${\gamma}$-ray outbursts (in November 2013 and March 2015) can be seen in ${\gamma}$-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of $411{\pm}85$ days, $352{\pm}79$ days, $310{\pm}57$ days, and $283{\pm}55$ days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths $B{\sim}2{\mu}T$ and electron Lorentz factors ${\gamma}$ ~ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale ${\tau}$ scales with frequency ${\nu}$ like ${\tau}{\propto}{\nu}^{-0.2}$. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the ${\gamma}$-ray outbursts. The spectral evolution is consistent with the 'generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second ${\gamma}$-ray event indicate that this ${\gamma}$-ray outburst might be an 'orphan' flare powered by the 'ring of fire' mechanism.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.1
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• pp.11-18
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• 2013

Human spaceflight experience in extra-vehicular activity (EVA) is limited to two regimes: the micro-gravity environment of Earth orbit, and the lunar surface environment at one-sixth of Earth's gravity. Future human missions to low-gravity bodies, including asteroids, comets, and the moons of Mars, will require EVA techniques that are beyond the current experience base. In order to develop robust approaches for exploring these small bodies, the dynamics associated with human exploration on low-gravity surface must be characterized. This paper examines the translational and rotational motion of an astronaut on the surface of a small body, and it is shown that the low-gravity environment will pose challenges to the surface mobility of an astronaut, unless new tools and EVA techniques are developed. Possibilities for addressing these challenges are explored, and utilization of the International Space Station to test operational concepts and hardware in preparation for a low-gravity surface EVA is discussed.

• Journal of the Korean housing association
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• v.14 no.3
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• pp.127-136
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• 2003

The purpose of this study is to establish concept about a plan direction of preschooler's library, and provide a design type of preschooler's library. As a result, the following findings were obtained: 1) For the preschooler's reading area, it should be segregated between schooler and preschooler. Because there is a difference between a library use action and a development characteristic, it needs to be segregated to avoid conflict using library for both of those groups. 2) The space composition of preschooler's library stands up, and of a tube considers a traffic line of a user according to the function and systematizes a child, and to cause an interest of preschoolers. 3) Furnitures and equipment of preschooler's library must arrange in consideration of human body size of a user in a tube.

• Korean Institute of Interior Design Journal
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• no.3
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• pp.71-77
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• 1994

The purpose of this study is to investigate the utilization of the interior environment in hotel lobby and to grasp the requests of visitors. The significance of the study is to illustrate the present characters of hotel lobby and to offer the basic data for future hotel projects. The materials for this study has been collected through questionnaires garnered from six deluxe hotels in Cheju, and statistically analyzed by the semantic differential scale of L. E. Osgood. The conclusion of this study as follows . 1) Hotel lobby is used as waiting space for a short time and frequent use is four times a day. The lobby is used by the quest for meeting , waiting as a resting place while it serves as the visitor's meeting and resting place. 2) The user prefers the lobby's open space. It is desirable for the area of activity of a quests and visitors to have separate entrances. The space composition of the lobby is centrally located between the room and subsidiary equipment. The hotel lobby has needed of a method which promotes lobby image through a magnificent view of the outside.

• Journal of Astronomy and Space Sciences
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• v.28 no.1
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• pp.1-7
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• 2011

Characteristics of latitude variations of sunspots in the northern and southern hemispheres are investigated using the daily sunspot area and its latitude during the period from 1874 to 2009. Solar magnetic activity is portrayed in the form of sunspot, regions of concentrated fresh magnetic fields observed on the surface of the Sun. By defining center-of-latitude (COL) as an area-weighted latitude, we find that COL is not monotonically decreasing as commonly assumed. In fact, small humps (or short plateaus) between solar minima can be seen around every solar maxima. We also find that when the northern (southern) hemisphere is magnetically dominant, COL is positive (negative), except the solar cycle 23, which may give a hint that these two phenomena are consistently regulated by one single mechanism. As a result of periodicity analysis, we find that several significant periodicities, such as, of ~5.5, ~11, ~49, and ~167 years.

• The Korean Journal of Air & Space Law and Policy
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• v.14
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• pp.331-379
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• 2001

The purpose of this study is provide better suggestions to utilize the small aircraft by examining current situations of those airports. Then, the results of this study should help explain about the Availability of the airports for small aircraft in view of airplane exhibition, air-sports activity fields for aviation sports population, aviation theme park, and aviation-related education facility. This study examines current situations of the small airports for small aircraft which have been limited in their utility and compares the airports at the same level abroad. By examining these airports, this paper can make suggestions for the Availability of the small airports. Significance of the study lies in providing businessmen planning to invest the small airports and owners of airports with profitable consequences. At the macro level, it is expected to have a more effective development of land and an increase of aviation market value.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.3
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• pp.47-57
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• 2009

The purpose of this study is to propose the design elements useful to give place identity to street space. The theory for place identity is studied and the components-Physical element, Sense, Program, Activity, Context-for identity of place is created. In the case study of SamcheongdongGil, the qualitative research method of Free Picturing Technique and Cognitive Mapping is executed and the samples gathered from the research are analyzed. In the process of analysis, the contents of qualitative evaluation by users is put in order as components for identity of place. Moreover, the design elements for street space are extracted from the case study and theories of urban design. The design elements are summarized as the followings: street pattern with high permeability, various streetscapes, greenscapes, semi public(private) spaces, the third places, public arts, transparent facades, and outdoor activities. Finally, the fruits and boundary of this study are described and the importance of place identity is.